power automation

Controlling a relay with a digital logic level.

noreply@blogger.com (automation) — Wed, 15 Jul 2009 15:48:00 +0000

The schematic below illustrates 4 methods of controlling a relay with a digital logic signal. Figure (A) can probably be used in most cases where the relay coil requires 100 mA or less and the input current is 2 milliamps or more. The resistor value (R) is determined from the input voltage and the available current. For example, a 5 volt input signal supplying 2 milliamps would require (5-.7)/.002 = 2150 ohms, or a 2.2K standard value. If the transistor has a minimum current gain of 50, there will be 100 mA of current available for the relay coil. The following table shows various resistor values that can be used to obtain various relay coil currents assuming a transistor current gain of 50 such as the 2N3053. 74XX refers to standard TTL logic, 74LSXX refers to low power TTL logic, 74HC is high speed CMOS and CD40XX is the older CMOS devices. The currents given are approximate values and may not be correct for all devices but should be close.

Input Voltage     Input Current     Relay coil current      Standard Resistor

 4             74LSXX  .0004       20 milliamps            8.2K
 4             74XX    .0008       40 milliamps            4.3K
 4             74SXX   .001        50 milliamps            3.3K
 5             74HCXX  .004        200 milliamps           1K
 6             74HCXX  .004        200 milliamps           1.3K
 5             CD40XX  .0003       15 milliamps            13K
 12            CD40XX  .0006       30 milliamps            18K

Figure B can be used when the input voltage is the same as the relay coil voltage. The voltage on the emitter of the transistor will be about 0.7 volts less than the input, so a 12 volt relay would operate on 11.3 which should be close enough. No resistor is needed since the emitter follower configuration presents a high impedance at the input. The input current will be the relay coil current divided by the transistor gain. For example a 120 ohm relay coil will draw 100 mA at 12 volts and if the transistor gain is 50, the input current will be about 2 milliamps.

Figure C can be used to provide additional gain when the input current is very small. You can also use a Darlington transistor in place of the two transistors which is a better approach, but this idea works just as well when you don't have a Darlington transistor handy. The overall gain will be the product of the individual gains of the two transistors or about 2500 for two transistor with a gain of 50 each. This will enable supplying over 250 mA to the relay with only 100 microamps of input current. The R value will depend on the input voltage and current and gain of the first transistor. For example, using a 5 volt input and 100 microamp current and transistor gain of 50, the R value will be 5 minus two diode drops (5 - 1.4) divided by the input current times 50, or about (5 - 1.4) / (.0001 * 50) = about 750 ohms. So this setup can be used when controlling heavy duty relays with low power CMOS logic signals.

Figure D can be used to reverse the relay action so that it engages when the input is low and disengages when the input is high. The R value is determined the same as in Figure A. The R1 value should be high enough to ensure saturation of the first stage and low enough to saturate the second stage. For example, if a 12 volt relay coil requires 100 mA and the driving transistor gain is 50, then the base current will be 100/50= 2 mA and the R1 value must be less than 6000 ohms so that 2 mA does not drop more than the supply voltage of 12. If the first transistor gain is 50 and the input current is 100 microamps, the collector current will be 5 mA and the R1 value must be greater than 2400 ohms so that 5 mA drops the entire supply voltage of 12. So we need to select something between these two limits of 2.4K to 6K, something around 4.3K would be near the midrange.

noreply@blogger.com (automation) — Tue, 07 Jul 2009 07:28:00 +0000

noreply@blogger.com (automation) — Tue, 07 Jul 2009 06:57:00 +0000

6/20/09Digital Photo Processes - LX3 in use
6/12/09Issues in speaker design - Crossover topology mistakes
6/12/09Links - Transducers with Beryllium cones or domes
5/27/09Links - A sensibly designed loudspeaker, the GRIMM AUDIO LS1
5/21/09 Publications - Recording and reproduction over two loudspeakers as heard live - AES Munich, May 2009
5/21/09Links - Review of the Audio Artistry VIVALDI open-baffle loudspeaker from 1996
4/9/09PLUTO supplies - Assembled, tested, and ready to play PLUTO-2.1 Electronics Modules are available again.
4/2/09Active Filters - Passive versions of filters 5, 6, and a fixed attenuator 10
3/23/09ORION FAQ - When do I need THOR subwoofers?
1/15/09PLUTO-2.1 - The latest update of PLUTO
12/6/08Links - The "Stereo Dipole"
12/6/08Links - Monte Kay's Home Theater
12/6/08Links - Horbach-Keele digital crossovers
12/3/08Digital Photo Processes - Waiting is over! The compact LX3 camera
11/12/08 Pluto-2 - A loudspeaker review by Peter Aczel of The Audio Critic
10/30/08FAQ 20 - What contributes to the polar response of ORION+?
10/22/08Design of loudspeakers - AES Convention, RMAF, Burning Amp
10/21/08Design of loudspeakers - First correspondence between SL and Laurie Fincham from KEF
10/20/08Publications - "Phantom images in 2-channel audio playback versus natural hearing processes"
8/22/08Pluto-2 owners check your Support Page for the latest update.
8/16/08Rocky Mountain Audio Fest - First public demonstrations of the ORION+ and Pluto-2.
8/16/08The Burning Amp Festival - I will give a talk about "The path to increased realism in 2-channel audio playback and recording"
8/4/08Links - Floyd Toole: Sound Reproduction - Loudspeakers and Rooms
7/20/08PLUTO-2 - Tweeter level adjustment
6/18/08Recording for stereo - Stereo recording angles
6/17/08Recording for stereo - Mapping from recording to playback
5/30/08Pluto-3 - A 3-way speaker with external crossover/equalizer and power amplifiers for someone who likes to test their skills.
5/30/08Pluto-2 - Construction details for conversion from PLUTO to Pluto-2 and to Pluto-2+
5/23/08ORION++ - Rear tweeter level adjustment
5/19/08Pluto-2 - A number of revisions to the original PLUTO for an easier to build and extended bass output 2-way system.
5/7/08Publication #24 - "Accurate sound reproduction from two loudspeakers in a living room"San Francisco AES Section Meeting. Presentation slides.
5/4/08Added Reference [5] for further reading about Investigation of energy storage.
4/26/08Added Tracks 19-28 to the Toneburst CD
4/23/08Added web page about Recording for stereo practices
4/16/08See the AES Convention paper which underlies the Room optimized stereophonic reproduction web page.
4/4/08The first open baffle loudspeaker?
4/3/08Audio CD with demonstrations of Auditory Scene Analysis
4/3/08H-frame loudspeaker from before 1936
3/30/08Review of the ORION++ by The Audio Critic
3/28/08A student version of CircuitMaker circuit analysis software is still available for download.
3/28/08Software signal generator for download.
3/26/08PLUTO owners check their support site for the Seas L16RN-SL circuit changes.
3/21/08Summarizing statement added to the Home page.
3/12/08A little homage to special friends: Russ Riley, Lyman Miller, Brian Elliott
3/10/08Added an Analog to digital conversion page to Digital Photo Processes.
2/29/08Added a Sharpness page to my camera investigation.
2/25/08Added photos from my Audio Artistry era to the Links page.
2/22/08I added an addendum to Suggestions and hearing.
2/20/08I am posting the Digital Photo Processes pages. This will highlight my limited bandwidth issues and probably force me into a more costly hosting plan. But then there is always the Website CD.
2/15/08A 1999 paper by B. Moore that deals with "Controversies and mysteries in spatial hearing" came to my attention again. I had forgotten about it. It would have helped me to understand the reason for the surprising similarity between an omni and a dipole in a reverberant room right away.
2/13/08It is likely that the website will be down on the 21st day of each month due to heavy traffic, but it will always resume on the 22nd when my 50 GB/mo bandwidth allowance period starts up again.
1/1/08I added the "cocktail party effect" to the paragraph about "Sound stream segregation" on the "Recording for stereo" page. Some readers were apparently confused about what Don is trying to accomplish.
12/22/07In case you wondered why the website was shut down yesterday for several hours, I had reached my monthly bandwidth allowance of 50 Gigabyte. Today starts a new monthly pay period with my ISP. If you own the Website CD, then you have access to 99% of the information here at all times and you probably will not notice any future interruption.
12/20/07-3The UK Chapter of the Audio Engineering Society keeps a full record of monthly talks on its website. The great variety of audio related subjects is educational and interesting.
12/20/07-2I receive about 300 email messages per day. 98% of that is junk and I just pull out those that have a relevant subject line. So be clear with the subject if you want to get through my Spam filter. Before writing please read my CAUTION.
12/20/07-1The Orion User Group is a good place to ask questions, get help and make contact. It also applies to PLUTO.
12/19/07-2If you are thinking of designing a box loudspeaker, then read Loudspeaker System Design. It covers many fundamental issues.
12/19/07-1A reminder to those who have bought documentation from LINKWITZ LAB. On the cover is the URL for a support page. Check it for the latest updates.
12/18/07-2My recent talk in London gives a summary of what has been learned here about loudspeaker design for accurate sound reproduction in relatively small rooms. ORION+ and PLUTO+ embody the key features that a loudspeaker must have. I hope that these prototypes will stimulate eventually some new loudspeaker developments for the high-end audio market so that a wider audience can hear what a simple 2-channel sound system is capable of. I am not holding my breath, though. The industry, its marketers and commentators are firmly locked into vented boxes and no fresh air comes in. Besides, the profit in this business is in cables, spikes, room tuning, etc. and now compact speakers for the iPod generation, but their hearing might be already damaged.
12/18/07-1The first and last links in the left hand column should let you find quickly what is new on the website by pointing to this page. This new page also gives me a convenient place to add timely comments

16bit quad SPI converter -LTC2754-16

noreply@blogger.com (automation) — Tue, 07 Jul 2009 06:46:00 +0000

Linear Technology's LTC2754-16 is a quad 16bit current output digital-to-analogue converter (DAC) that it says achieves ±1LSB integral nonlinearity and differential nonlinearity.
All four DACs can be software programmed or pin strapped for one of six unipolar or bipolar output ranges via a four wire serial interface. The LTC2754-16's DC specifications and SoftSpan output configurability make it suitable for multichannel data acquisition modules and automated test equipment. A pin and software compatible 12bit option is also available, designed to allow a transition between different resolutions in the end product. According to Linear, the LTC2754-16 is capable of outputting six software programmable unipolar and bipolar output ranges up to ±10V. The six SoftSpan output voltage ranges include two unipolar ranges (0 to 5V, 0 to 10V) and four bipolar ranges (±10, ±5, ±2.5, -2.5 to +7.5V). Voltage controlled offset and gain adjustment pins are also included for each DAC, making it possible to fine tune each DAC output. The LTC2754-16 outputs any of the six SoftSpan ranges while operating from a single 2.7 to 5.5V supply and drawing 1uA maximum supply current. The LTC2754-16 also incorporates a full scale settling time of 2us and low glitch impulse of 0.26nV•s with a 3V supply or 1.25nV•s with a 5V supply. Its 2MHz multiplying bandwidth and AC specifications are designed for applications such as waveform generation. The LTC2754-12 is a pin compatible 12bit device, with both 16bit and 12bit versions available in 7 x 8mm QFN-52 packages. The serial LTC2754 joins a family of quad, dual and single DACs (LTC2755/LTC2753/LTC2751) that communicate via parallel I/O. The entire family is available in commercial and industrial temperature ranges.

AuthorChris Shaw

Supporting Information
http://www.linear.com/

Optical transistor created from single molecule

noreply@blogger.com (automation) — Tue, 07 Jul 2009 06:42:00 +0000

Researchers ETH Zurich researchers claim to have successfully created an optical transistor from a single molecule. The move is said to bring an optical computer 'one step closer'.
By using one laser beam to prepare the quantum state of a single molecule in a controlled fashion, scientists could significantly attenuate or amplify a second laser beam. This mode of operation is identical to that of a conventional transistor, in which electrical potential can be used to modulate a second signal. The researchers used the fact that a molecule's energy is quantised:
when laser light strikes a molecule that is in its ground state, the light is absorbed and the laser beam quenched. The absorbed energy can then be released with a second light beam. According to ETH Zurich, the beam changes the molecule's quantum state, with the result that the light beam is amplified – the same principle as used by the laser. Vahid Sandoghdar, Professor at the Laboratory of Physical Chemistry of ETH Zurich, said: "Comparing the current state of this technology with that of electronics, we are somewhat closer to the vacuum tube amplifiers that were around in the 1950s than we are to today's integrated circuits." The effect has been created by cooling the molecule to 1K. At this temperature molecules appear to increase the surface area available for interaction with light and the enlarged surface area was approximately the diameter of the focused laser beam. Prof Sandoghdar added: "Many years of research will be needed before photons replace electrons in transistors. In the meantime, scientists will learn to manipulate and control quantum systems in a targeted way, moving them closer to the dream of a quantum computer."

AuthorGraham Pitcher

Wireless Modbus I/O

noreply@blogger.com (automation) — Mon, 01 Jun 2009 05:07:00 +0000

Model: ZZxD-Nx-xR series
Wireless Modbus I/O
Modular and Customizable Wireless Replacement!
Introduction
Wireless Modbus I/O - flexible enough to fit your applications. Zlinx plug-n-play modular units
from B&B Electronics combine traditional Modbus RTU remote analog and discrete I/O with built-in
wireless connectivity - reducing cost, simplifying installation and support. Wireless RTU serves as
Modbus slave RTU in radio-based SCADA systems, or as a peer-to-peer communication platform.
Features
DIN Rail Package Easy installation; conserves panel space (versus panel mount modems).
3 Ranges Available Short, Medium, Long range. Don’t spend more money on longer distance radios if you don’t
need the distance.
Active Repeaters Place I/O modules where they need to go, by the sensors. With repeater built-in functionality
(-MR and -LR models only), you can build up a security path for all your critical communications.
Modular Customize it to your application. Just snap on your I/O and you're ready to go.
10-48 VDC Power Input Rugged input power circuit allows insertion to most control power configurations. Can utilize
industrial power supply.
Wide Temperature/
Industrial Grade
Meets most indoor or outdoor applications. Rugged circuitry prevents signal degradation versus
lower temperature rated wireless devices.
Modbus Compatible Interface using industry standard Modbus protocol. Connect to Wonderware, Labview or other

noreply@blogger.com (automation) — Mon, 01 Jun 2009 05:07:00 +0000

noreply@blogger.com (automation) — Sun, 31 May 2009 18:34:00 +0000

noreply@blogger.com (automation) — Thu, 21 May 2009 18:00:00 +0000

Introduction
This project is mainly in answer to those for whom no amount of power is enough. I have lost count of the number of times people have asked if it's alright to increase the supply voltage on every circuit published, and in general the answer is no - it's not alright. Every design on this site is optimised for the stated power. There is always some flexibility, but you must be very careful to make sure that transistor safe operating area (SOA) is not exceeded. There is also a maximum voltage for any semiconductor, and devices must be selected to ensure they are used within their ratings.
While (lateral) MOSFETs offer some real advantages, they are relatively expensive, and difficult to obtain with voltage ratings above 200V. Vertical MOSFETs (e.g. HEXFETs and the like) are a possibility, but suffer gross non-linearity at very low currents. Therefore, a relatively high quiescent current is needed, and this makes heat removal that much more difficult. There are other issues as well, but a discussion of them is outside the scope of this article.
WARNINGThis project describes an amplifier, power supply and tests procedures that are all inherently dangerous. Nothing described in this article should even be considered unless you are fully experienced, know exactly what you are doing, and are willing to take full 100% responsibility for what you do. There are aspects of the design that may require analysis, fault-finding and/or modification.By continuing to read this article and/or commencing work on the project, you provide your implicit agreement that ESP shall be held harmless for any loss or damage, howsoever caused. You accept all risks to life, limb and finances (this will be a very expensive undertaking) that the project may present. ESP accepts that there may be errors and/or omissions in the text and diagrams that follow, and you accept that these become your responsibility should you decide to build the project.
No assistance whatsoever will be provided for this project! If you ask me questions about it, they WILL NOT be answered!
Capable of 2kW peak and a minimum of 1.5kW continuous, it has to be said that this amplifier will blow up any speaker connected to it. Regardless of the claimed power that various drivers can handle, they can't. To put this whole issue into perspective, take the most powerful and robust driver you can (8 ohms), and connect it directly to the 110V mains (I recommend this as a 'thought experiment', rather than actually doing it!). 110V RMS into 8 ohms is 1,500W. How long would you expect the speaker to last? Most will be toast within perhaps 30 seconds or less! A very few will last slightly longer, but none will take that level of abuse for more than a few minutes.
I strongly suggest that you read Power Vs. Efficiency before continuing.
Have a look at the voicecoil of any speaker. Imagine how hot it will get with even 100W of continuous power - feel a 100W light bulb - 100W is enough to make any small mass get very hot indeed, very quickly. 1,500W is an awesome (scary even) amount of power! Look at the size cable needed to carry 20A, then look at the wire size used for the voicecoil. If you don't see a real problem, then I suggest you abandon electronics take up flower arranging as a hobby.
It must be understood that this is a 'brute force' approach, and that much is deliberate. Although it would be possible to use more finesse in the final design (such as using a tracking power supply, or a Class-G multi supply rail approach), these are harder to design, and would require building a prototype to verify performance. Since I have no need at all for this much power, I am not prepared to spend the time and money to build and test something I'll never need.
I know that no speaker I have (or am likely to ever have) can take that much power, and the amp would be a waste of money. Should someone be silly enough to pay me the AU$12,000 I would charge to build a mono version of the amp, then I would happily do so. So, I am confident that it will work as described, but it will almost certainly never be built by me. I hope that my readers share my pragmatism.
Should you (wisely) decide that this amp is as silly as I think it is, then go back to Project 68. The dual board version with ±70V supplies is still capable of destroying many drivers, but there are loudspeakers than can take its output short term. This makes it ideal for subwoofer duty, easily giving over 500W into 4 ohms for transient signals, or 450W continuous (which it can do all day with a fan forced heatsink). This is a proven design, and although not inexpensive, it still represents fairly good value for such a high power amplifier. IMHO there is no point trying for more power, as few drivers can handle more than a couple of hundred Watts without suffering severe power compression.
Description
First, let's look at the requirements to get 1.5kW into 4 ohms. We need 77.5V RMS across the load, but we need to have a bit more, because the supply voltage will collapse under load, and there will always be some voltage lost across the transistors, emitter resistors, etc. The supply voltage needs to be ...
VDC = VRMS * 1.414VDC = 77.5 * 1.414 = ±109.6V DC
Since we have not allowed for losses yet, we need to allow around 3-5V for the amplifier, and an additional 10V or so to allow for the supply voltage falling when the amp is loaded. The higher the current, the greater the I²R (resistive) losses, so 5V was used in this design. With a transformer rated at 2 x 90V, this gives an unloaded supply of ±130V DC (260V DC total), so the supply has to be treated with extreme care - it is very dangerous indeed. There is an old term used by those who work with high voltages ...
One flash and you're ash !
... and you would do well to remember this. Add on the auxiliary supplies (taking the total to 270V DC), and the supply is capable of killing you several times over, even after it is disconnected from the mains. Even the output signal to the speakers must be treated with care, as 77V is enough to give you a nasty shock.
The final supply voltage will be around ±120V, because even with the biggest transformer and filter capacitors, you will lose voltage. The current demand is also prodigious. With a peak voltage of 110V, the peak supply current is 27.5A into a 4 ohm load. RMS speaker current is just under 20A at full power. Everything you thought you knew about amp building needs to be re-thought. PCB tracks cannot be used for these current levels, because the extra resistance will cause current balancing problems with the power transistors. All wiring needs to be extremely robust, and must absolutely not allow any possibility of contact (it will kill you) or short circuits (which will kill the amp). The supply is capable of vaporising thin wires and PCB tracks.
Because of the issues discussed above, bipolar transistors were selected as most appropriate for the output stage. This was primarily dictated by the supply voltage, which exceeds that allowed for any affordable lateral MOSFET. It is even a challenge for affordable BJTs, but the MJ15004/5 or MJ21193/4 pairs are within ratings, so these are suggested. While I would normally specify a compound pair (also called a Sziklai pair) for the output stage, in this case it is a triple stage, and the Sziklai pair (much as I like it) can be prone to oscillation, primarily on the negative side. This is highly undesirable for an amp with the power of that described here. Despite reservations, the triple Darlington is more appropriate for this application.
Next, we need to look closely at the power dissipation of the devices. Worst case resistive load dissipation occurs when ½ the supply voltage is across both load and transistors. This occurs at a voltage of 65V across the load (worst case), and gives a peak (instantaneous) power in both load and output stage of ...
P = V² / R = 65² / 4 = 1056W
This is only a starting point, because we must have a safety margin. Remember that the peak dissipation into a reactive load with a 45° phase angle is almost double that calculated above, about 1900W. If the transistors can be maintained at 25°C (not likely), that's fine, but we need to add more to allow for elevated temperature. I have elected to use 9 output devices, with a tenth device used as a driver. This maintains worst case peak dissipation at 212W - not much of a safety margin, but it should be ok in practice - in part because the supply voltage will collapse under load. Cooling is vitally important - this amplifier will need a very substantial heatsink, and fan cooling is essential. Fans should cut in at no higher than 35°C.
The MJ15024/5 (or MJ21193/4) devices are TO-3 packages, and are specified for 250W dissipation at 25°C. It is worth noting that the driver in this arrangement will contribute some of the output, but it only reduces the main transistor's peak dissipation by about 5W. TO-3 devices are specified because they have the highest power rating of any general purpose package, because thermal resistance is lower than any flat-pack plastic device.
The MJE340/350 pre-drivers reduce the loading on the VAS (voltage amplification stage) and ensures good linearity with acceptably low dissipation of the VAS transistor (Q4) and its current source (Q6). Even so, with around 12mA through the VAS, dissipation is 0.72W, so Q4, Q6, Q9 and Q10 must have heatsinks (or a common heatsink that is suitable for the power dissipated). The bias servo transistor (Q5) should be mounted in thermal contact with the main heatsink.
The protection circuit will limit the peak transistor power to around 180W, with a short circuit current of about 12A. This is slightly outside the SOA of the output transistors. Although it is possible to get the protection circuit to force the output stage to follow the SOA curve, this almost inevitably means that maximum power cannot be achieved unless the protection circuit is made considerably more complex. For an amp that (hopefully) will never be built, this was not warranted. The alternative is to add more output transistors.
Figure 1 - 1.5kW Power AmplifierIntroduction
This project is mainly in answer to those for whom no amount of power is enough. I have lost count of the number of times people have asked if it's alright to increase the supply voltage on every circuit published, and in general the answer is no - it's not alright. Every design on this site is optimised for the stated power. There is always some flexibility, but you must be very careful to make sure that transistor safe operating area (SOA) is not exceeded. There is also a maximum voltage for any semiconductor, and devices must be selected to ensure they are used within their ratings.
While (lateral) MOSFETs offer some real advantages, they are relatively expensive, and difficult to obtain with voltage ratings above 200V. Vertical MOSFETs (e.g. HEXFETs and the like) are a possibility, but suffer gross non-linearity at very low currents. Therefore, a relatively high quiescent current is needed, and this makes heat removal that much more difficult. There are other issues as well, but a discussion of them is outside the scope of this article.
WARNINGThis project describes an amplifier, power supply and tests procedures that are all inherently dangerous. Nothing described in this article should even be considered unless you are fully experienced, know exactly what you are doing, and are willing to take full 100% responsibility for what you do. There are aspects of the design that may require analysis, fault-finding and/or modification.By continuing to read this article and/or commencing work on the project, you provide your implicit agreement that ESP shall be held harmless for any loss or damage, howsoever caused. You accept all risks to life, limb and finances (this will be a very expensive undertaking) that the project may present. ESP accepts that there may be errors and/or omissions in the text and diagrams that follow, and you accept that these become your responsibility should you decide to build the project.
No assistance whatsoever will be provided for this project! If you ask me questions about it, they WILL NOT be answered!
Capable of 2kW peak and a minimum of 1.5kW continuous, it has to be said that this amplifier will blow up any speaker connected to it. Regardless of the claimed power that various drivers can handle, they can't. To put this whole issue into perspective, take the most powerful and robust driver you can (8 ohms), and connect it directly to the 110V mains (I recommend this as a 'thought experiment', rather than actually doing it!). 110V RMS into 8 ohms is 1,500W. How long would you expect the speaker to last? Most will be toast within perhaps 30 seconds or less! A very few will last slightly longer, but none will take that level of abuse for more than a few minutes.
I strongly suggest that you read Power Vs. Efficiency before continuing.
Have a look at the voicecoil of any speaker. Imagine how hot it will get with even 100W of continuous power - feel a 100W light bulb - 100W is enough to make any small mass get very hot indeed, very quickly. 1,500W is an awesome (scary even) amount of power! Look at the size cable needed to carry 20A, then look at the wire size used for the voicecoil. If you don't see a real problem, then I suggest you abandon electronics take up flower arranging as a hobby.
It must be understood that this is a 'brute force' approach, and that much is deliberate. Although it would be possible to use more finesse in the final design (such as using a tracking power supply, or a Class-G multi supply rail approach), these are harder to design, and would require building a prototype to verify performance. Since I have no need at all for this much power, I am not prepared to spend the time and money to build and test something I'll never need.
I know that no speaker I have (or am likely to ever have) can take that much power, and the amp would be a waste of money. Should someone be silly enough to pay me the AU$12,000 I would charge to build a mono version of the amp, then I would happily do so. So, I am confident that it will work as described, but it will almost certainly never be built by me. I hope that my readers share my pragmatism.
Should you (wisely) decide that this amp is as silly as I think it is, then go back to Project 68. The dual board version with ±70V supplies is still capable of destroying many drivers, but there are loudspeakers than can take its output short term. This makes it ideal for subwoofer duty, easily giving over 500W into 4 ohms for transient signals, or 450W continuous (which it can do all day with a fan forced heatsink). This is a proven design, and although not inexpensive, it still represents fairly good value for such a high power amplifier. IMHO there is no point trying for more power, as few drivers can handle more than a couple of hundred Watts without suffering severe power compression.
Description
First, let's look at the requirements to get 1.5kW into 4 ohms. We need 77.5V RMS across the load, but we need to have a bit more, because the supply voltage will collapse under load, and there will always be some voltage lost across the transistors, emitter resistors, etc. The supply voltage needs to be ...
VDC = VRMS * 1.414VDC = 77.5 * 1.414 = ±109.6V DC
Since we have not allowed for losses yet, we need to allow around 3-5V for the amplifier, and an additional 10V or so to allow for the supply voltage falling when the amp is loaded. The higher the current, the greater the I²R (resistive) losses, so 5V was used in this design. With a transformer rated at 2 x 90V, this gives an unloaded supply of ±130V DC (260V DC total), so the supply has to be treated with extreme care - it is very dangerous indeed. There is an old term used by those who work with high voltages ...
One flash and you're ash !
... and you would do well to remember this. Add on the auxiliary supplies (taking the total to 270V DC), and the supply is capable of killing you several times over, even after it is disconnected from the mains. Even the output signal to the speakers must be treated with care, as 77V is enough to give you a nasty shock.
The final supply voltage will be around ±120V, because even with the biggest transformer and filter capacitors, you will lose voltage. The current demand is also prodigious. With a peak voltage of 110V, the peak supply current is 27.5A into a 4 ohm load. RMS speaker current is just under 20A at full power. Everything you thought you knew about amp building needs to be re-thought. PCB tracks cannot be used for these current levels, because the extra resistance will cause current balancing problems with the power transistors. All wiring needs to be extremely robust, and must absolutely not allow any possibility of contact (it will kill you) or short circuits (which will kill the amp). The supply is capable of vaporising thin wires and PCB tracks.
Because of the issues discussed above, bipolar transistors were selected as most appropriate for the output stage. This was primarily dictated by the supply voltage, which exceeds that allowed for any affordable lateral MOSFET. It is even a challenge for affordable BJTs, but the MJ15004/5 or MJ21193/4 pairs are within ratings, so these are suggested. While I would normally specify a compound pair (also called a Sziklai pair) for the output stage, in this case it is a triple stage, and the Sziklai pair (much as I like it) can be prone to oscillation, primarily on the negative side. This is highly undesirable for an amp with the power of that described here. Despite reservations, the triple Darlington is more appropriate for this application.
Next, we need to look closely at the power dissipation of the devices. Worst case resistive load dissipation occurs when ½ the supply voltage is across both load and transistors. This occurs at a voltage of 65V across the load (worst case), and gives a peak (instantaneous) power in both load and output stage of ...
P = V² / R = 65² / 4 = 1056W
This is only a starting point, because we must have a safety margin. Remember that the peak dissipation into a reactive load with a 45° phase angle is almost double that calculated above, about 1900W. If the transistors can be maintained at 25°C (not likely), that's fine, but we need to add more to allow for elevated temperature. I have elected to use 9 output devices, with a tenth device used as a driver. This maintains worst case peak dissipation at 212W - not much of a safety margin, but it should be ok in practice - in part because the supply voltage will collapse under load. Cooling is vitally important - this amplifier will need a very substantial heatsink, and fan cooling is essential. Fans should cut in at no higher than 35°C.
The MJ15024/5 (or MJ21193/4) devices are TO-3 packages, and are specified for 250W dissipation at 25°C. It is worth noting that the driver in this arrangement will contribute some of the output, but it only reduces the main transistor's peak dissipation by about 5W. TO-3 devices are specified because they have the highest power rating of any general purpose package, because thermal resistance is lower than any flat-pack plastic device.
The MJE340/350 pre-drivers reduce the loading on the VAS (voltage amplification stage) and ensures good linearity with acceptably low dissipation of the VAS transistor (Q4) and its current source (Q6). Even so, with around 12mA through the VAS, dissipation is 0.72W, so Q4, Q6, Q9 and Q10 must have heatsinks (or a common heatsink that is suitable for the power dissipated). The bias servo transistor (Q5) should be mounted in thermal contact with the main heatsink.
The protection circuit will limit the peak transistor power to around 180W, with a short circuit current of about 12A. This is slightly outside the SOA of the output transistors. Although it is possible to get the protection circuit to force the output stage to follow the SOA curve, this almost inevitably means that maximum power cannot be achieved unless the protection circuit is made considerably more complex. For an amp that (hopefully) will never be built, this was not warranted. The alternative is to add more output transistors.
Figure 1 - 1.5kW Power Amplifier
The circuit is completely conventional, using a long tailed pair input stage, direct coupled to the VAS. No current mirror was used for the LTP, as this increases open loop gain and may give rise to stability issues. In a very high power amp, stability is paramount. The amp must never oscillate under any normal load condition, because the heat created can cause almost instant transistor failure.
* Note: It is imperative that Q5 (the bias servo transistor) is mounted on the heatsink, in excellent thermal contact. This is because, unlike most of my other designs, this amp uses conventional Darlington output configuration. It is necessary to use a Darlington arrangement (or a low power Darlington transistor as shown) for Q5 to ensure that the bias remains at a safe value with temperature. This is left to the constructor, because as noted I will not provide technical assistance for this design. There is probably good cause to model and test this aspect of the design very carefully, because it is so important. The arrangement as shown will reduce quiescent current at elevated temperatures. For example, if total Iq at 24°C is 165mA, this will fall to ~40mA at 70°C. This is probably fine, because there is some delay between the a power 'surge' and the output transistors transferring their heat to the bias servo via the heatsink.
The additional feedback components (R6a and C3a, shown dotted) are optional. They may be needed to ensure stability. The output 'flyback' diodes (D9 and D10) will normally only ever conduct if the protection circuit operates while the amp is driving a reactive load. The 1N5404 diodes can withstand a peak non-repetitive current of 200A. Higher rated components may be used if desired. The voltage rating needs to be at least 400V.
The 100 ohm trimpot used in the LTP is used to adjust the DC offset to minimum. With the component values as shown, offset should be within ±25mV, before adjustment. The second trimpot is used to set quiescent current. This should be set to a value just sufficient to minimise crossover distortion. High quiescent current is not desirable, simply because of the power dissipation. Quiescent current is set so that 150mV is measured across R19 or R20.
You will also note that SOA protection has been incorporated. I don't like protection circuits very much, because they can cause very audible sound quality degradation if they operate, but in an amplifier with so many transistors (not to mention the massive power supply needed), the available energy will cause instantaneous destruction of the output stage if protection is not used. Would I actually risk applying a short circuit to the output terminals? No, I would not. I haven't built this design, and I have no intention of doing so. A full simulation tells me that the protection circuits should ensure that nothing blows up, but I do not intend to find out.
Input sensitivity is about 1.77V for 900W into 8 ohms, or 1800W into 4 ohms, or 1.6V RMS for rated power (1.5kW into 4 ohms).
More Power?Believe it or not, the design can be pushed even further. You will need to add more power transistors and upgrade the power supply though. Supply voltages of up to ±150V can be used without changing anything other than increasing the number of output devices. Although the MJ15024/5 are rated at 250V, they will take more because the base is tied to the emitter with a very low resistance. 1200W into 8 ohms is quite possible, with around 2kW into 4 ohms (or 4kW / 8 ohms in BTL configuration). I suggest that the number of output devices be increased by at least 25% - a total of 13 devices for each supply rail (26 in total, including drivers).
There would seem to be some valid reasons for using MOSFETs, not least because the voltage rating is easily achieved with low cost (switching) devices. The use of high voltage devices with a relatively high RDSon is necessary to minimise distortion at low levels. Given that these usually use the TO220 package, I recommend that peak dissipation is limited to 35W or less (~15W average). The TO220 package is convenient, but is hopeless for transferring significant heat from junction to heatsink. This would require around 50 x TO220 devices for each rail (100 in all). Remember that vertical MOSFETs must be matched, so expect to purchase at least 300-500 transistors to allow for matching. All parallel devices must have as close as possible to the same VTH (threshold voltage, gate to source). Note that a vertical MOSFET version has been simulated, built and tested at lower power (a couple of hundred Watts), but is not shown here.
Given that the peak output power of the amp as described will be around 950W into 8 ohms and close to 1800W into 4 ohms, I doubt that any upgrades will be needed .
2 Ohms?No. Not a chance. Adding more transistors will certainly allow it - in fact, the transistors there already will come very close. The problem is simply a matter of current. Over 40A RMS at full power just means that large quantities of the output power will be dissipated as heat in connectors and speaker leads, and it's just not worth the effort. Who wants to drag around industrial welding cables as speaker leads? Even at 4 Ohms, you have to deal with over 20A RMS (and 30A peaks), so leads and connectors need to be very robust.
Power Supply
The power supply needed for an amp of this size is massive. Grown welding machines will look at it and cry. For intermittent operation, you need a minimum of a 1kVA transformer (or 1.5kVA for the 2kW version), and it will have to be custom made because of the voltages used. If you expect to run the amp at continuous high power, then transformers should be 2kVA and 3kVA respectively. Filter capacitors will pose a problem - because you need caps rated for 150V, these will be hard to find. Because high voltage high value caps can be difficult to find, it may be necessary to use two electros in series for each capacitor location. This is the arrangement shown. You must include the resistors in parallel - these equalise the voltage across each capacitor so that they have the same voltage. Remember to verify the ripple current rating! This can be expected to be over 10A, and under-rated capacitors will blow up.
Another difficulty is the bridge rectifier. Although 35A bridges would seem to be adequate, the peak repetitive current is so high that they may not be up to the task. I suggest that you use two (or even three) in parallel as shown. The bridge rectifier voltage rating should be a minimum of 400V, and they must be mounted on a substantial heatsink.
Figure 2 - Power Supply
Note that the supply shown is suitable for one amplifier only! For a stereo version, you will need a transformer with double the rating for a single amp, and double the capacitance. Although a standard P39 soft start circuit controller board will work fine, the resistors will need to be upgraded. The series soft start resistor should be around 33 ohms, and rated at 50W or more. As you can see, the power switch simply applies low voltage AC to the auxiliary supply bridge rectifier and to the soft start circuit via relay contacts. The relay is located on the control board which also has DC and thermal detection.
The additional 5V supplies shown will give a small increase in peak output power, but may be omitted. With the extra voltage, peak power is about 2,048W, vs 1,920W without it. While this may appear to be worthwhile, in real terms it is only 0.5dB more. You will gain far more by using heavier gauge mains and speaker leads or a different power outlet.
DC Protection - You cannot use output relays with this amplifier! Should a DC fault be detected at the output, the only option is to switch off the power. A relay that will withstand breaking 115V or 150V DC at 25A or more is going to be hard to get, and extremely expensive. Although the speakers will be subjected to the full supply voltage until the filter caps discharge, as the builder of the amp, you are confident that they will withstand the power.
Me, I'm not so sure.
You will notice that the AC mains is specified for 230/240V only. Use at 115V is not recommended because of the current. At full power, the amp will draw a minimum of 10A (slightly above the transformer rating), but with 115V, that will increase to over 20A. The losses are too high with that much current, so in 115/120V countries, I suggest that the amp be connected to a two phase power source as a matter of course. Even at the higher supply voltage, the limit for a standard power outlet in Australia is 10A, so the continuous power input is limited to 2400W, and continuous power output will be substantially less than this.
Figure 3 - Protection and Control Circuits
The control circuit need not be complex, but is very important. Although P33 could be used for DC detection, it would be better to use a dedicated circuit (which has not been designed yet). The thermal sensors can be transistors or dedicated ICs, and a simple comparator circuit detects that the temperature is above the trip value of 35°C to turn on the fans. The fans need to be high output types, as they will be called upon to dispose of a prodigious amount of heat when the amp is being pushed. Thermal switches act as a backup - if the fan controller fails to operate for any reason, normally open thermal switches will start the fans.
Water cooling is a viable option for an amp like this, especially for long term high power usage in a fixed location.
Construction
If you decide to build this amp, you will be prepared to spend a lot of money and time. You will also have sufficient experience to be able to work out the construction processes yourself. For a single channel, the parts alone will cost upwards of AU$1,000, probably closer to AU$1,500 or even more. Just the power transformer is likely to be around $250-300, and there's probably another $300 or more for filter capacitors. You will need a heatsink rated at about 0.03°C/W with forced cooling. I cannot suggest a suitable heatsink, but you can be sure that it will be large and expensive.
Please note that this project is provided as information only, and I will not provide any assistance to prospective builders. The entire project is your responsibility if you want to take it on.
Testing
If you are crazy enough to build this amp, then you will have sufficient skills to be able to work out what is needed to test it. Remember that the smallest mistake could easily despatch many expensive transistors, blow the tracks off a PCB, melt wiring, and all manner of other distasteful possibilities.
As with any high powered amplifier, initial testing should be done with a current limited power supply and no load. The amp will be functional with as little as ±10V or less, and the power supply and complete amplifier must be tested using a Variac (bypassing the soft start for initial tests). The Variac needs to be rated the same as the power transformer (i.e. at least 2kVA).
I will leave the remainder of the test procedure to the constructor, since the only people who should even attempt building an amp of this power should be very experienced with high power systems. If this does not describe you, then don't even think about it.
The circuit is completely conventional, using a long tailed pair input stage, direct coupled to the VAS. No current mirror was used for the LTP, as this increases open loop gain and may give rise to stability issues. In a very high power amp, stability is paramount. The amp must never oscillate under any normal load condition, because the heat created can cause almost instant transistor failure.
* Note: It is imperative that Q5 (the bias servo transistor) is mounted on the heatsink, in excellent thermal contact. This is because, unlike most of my other designs, this amp uses conventional Darlington output configuration. It is necessary to use a Darlington arrangement (or a low power Darlington transistor as shown) for Q5 to ensure that the bias remains at a safe value with temperature. This is left to the constructor, because as noted I will not provide technical assistance for this design. There is probably good cause to model and test this aspect of the design very carefully, because it is so important. The arrangement as shown will reduce quiescent current at elevated temperatures. For example, if total Iq at 24°C is 165mA, this will fall to ~40mA at 70°C. This is probably fine, because there is some delay between the a power 'surge' and the output transistors transferring their heat to the bias servo via the heatsink.
The additional feedback components (R6a and C3a, shown dotted) are optional. They may be needed to ensure stability. The output 'flyback' diodes (D9 and D10) will normally only ever conduct if the protection circuit operates while the amp is driving a reactive load. The 1N5404 diodes can withstand a peak non-repetitive current of 200A. Higher rated components may be used if desired. The voltage rating needs to be at least 400V.
The 100 ohm trimpot used in the LTP is used to adjust the DC offset to minimum. With the component values as shown, offset should be within ±25mV, before adjustment. The second trimpot is used to set quiescent current. This should be set to a value just sufficient to minimise crossover distortion. High quiescent current is not desirable, simply because of the power dissipation. Quiescent current is set so that 150mV is measured across R19 or R20.
You will also note that SOA protection has been incorporated. I don't like protection circuits very much, because they can cause very audible sound quality degradation if they operate, but in an amplifier with so many transistors (not to mention the massive power supply needed), the available energy will cause instantaneous destruction of the output stage if protection is not used. Would I actually risk applying a short circuit to the output terminals? No, I would not. I haven't built this design, and I have no intention of doing so. A full simulation tells me that the protection circuits should ensure that nothing blows up, but I do not intend to find out.
Input sensitivity is about 1.77V for 900W into 8 ohms, or 1800W into 4 ohms, or 1.6V RMS for rated power (1.5kW into 4 ohms).
More Power?Believe it or not, the design can be pushed even further. You will need to add more power transistors and upgrade the power supply though. Supply voltages of up to ±150V can be used without changing anything other than increasing the number of output devices. Although the MJ15024/5 are rated at 250V, they will take more because the base is tied to the emitter with a very low resistance. 1200W into 8 ohms is quite possible, with around 2kW into 4 ohms (or 4kW / 8 ohms in BTL configuration). I suggest that the number of output devices be increased by at least 25% - a total of 13 devices for each supply rail (26 in total, including drivers).
There would seem to be some valid reasons for using MOSFETs, not least because the voltage rating is easily achieved with low cost (switching) devices. The use of high voltage devices with a relatively high RDSon is necessary to minimise distortion at low levels. Given that these usually use the TO220 package, I recommend that peak dissipation is limited to 35W or less (~15W average). The TO220 package is convenient, but is hopeless for transferring significant heat from junction to heatsink. This would require around 50 x TO220 devices for each rail (100 in all). Remember that vertical MOSFETs must be matched, so expect to purchase at least 300-500 transistors to allow for matching. All parallel devices must have as close as possible to the same VTH (threshold voltage, gate to source). Note that a vertical MOSFET version has been simulated, built and tested at lower power (a couple of hundred Watts), but is not shown here.
Given that the peak output power of the amp as described will be around 950W into 8 ohms and close to 1800W into 4 ohms, I doubt that any upgrades will be needed .
2 Ohms?No. Not a chance. Adding more transistors will certainly allow it - in fact, the transistors there already will come very close. The problem is simply a matter of current. Over 40A RMS at full power just means that large quantities of the output power will be dissipated as heat in connectors and speaker leads, and it's just not worth the effort. Who wants to drag around industrial welding cables as speaker leads? Even at 4 Ohms, you have to deal with over 20A RMS (and 30A peaks), so leads and connectors need to be very robust.
Power Supply
The power supply needed for an amp of this size is massive. Grown welding machines will look at it and cry. For intermittent operation, you need a minimum of a 1kVA transformer (or 1.5kVA for the 2kW version), and it will have to be custom made because of the voltages used. If you expect to run the amp at continuous high power, then transformers should be 2kVA and 3kVA respectively. Filter capacitors will pose a problem - because you need caps rated for 150V, these will be hard to find. Because high voltage high value caps can be difficult to find, it may be necessary to use two electros in series for each capacitor location. This is the arrangement shown. You must include the resistors in parallel - these equalise the voltage across each capacitor so that they have the same voltage. Remember to verify the ripple current rating! This can be expected to be over 10A, and under-rated capacitors will blow up.
Another difficulty is the bridge rectifier. Although 35A bridges would seem to be adequate, the peak repetitive current is so high that they may not be up to the task. I suggest that you use two (or even three) in parallel as shown. The bridge rectifier voltage rating should be a minimum of 400V, and they must be mounted on a substantial heatsink.
Figure 2 - Power Supply
Note that the supply shown is suitable for one amplifier only! For a stereo version, you will need a transformer with double the rating for a single amp, and double the capacitance. Although a standard P39 soft start circuit controller board will work fine, the resistors will need to be upgraded. The series soft start resistor should be around 33 ohms, and rated at 50W or more. As you can see, the power switch simply applies low voltage AC to the auxiliary supply bridge rectifier and to the soft start circuit via relay contacts. The relay is located on the control board which also has DC and thermal detection.
The additional 5V supplies shown will give a small increase in peak output power, but may be omitted. With the extra voltage, peak power is about 2,048W, vs 1,920W without it. While this may appear to be worthwhile, in real terms it is only 0.5dB more. You will gain far more by using heavier gauge mains and speaker leads or a different power outlet.
DC Protection - You cannot use output relays with this amplifier! Should a DC fault be detected at the output, the only option is to switch off the power. A relay that will withstand breaking 115V or 150V DC at 25A or more is going to be hard to get, and extremely expensive. Although the speakers will be subjected to the full supply voltage until the filter caps discharge, as the builder of the amp, you are confident that they will withstand the power.
Me, I'm not so sure.
You will notice that the AC mains is specified for 230/240V only. Use at 115V is not recommended because of the current. At full power, the amp will draw a minimum of 10A (slightly above the transformer rating), but with 115V, that will increase to over 20A. The losses are too high with that much current, so in 115/120V countries, I suggest that the amp be connected to a two phase power source as a matter of course. Even at the higher supply voltage, the limit for a standard power outlet in Australia is 10A, so the continuous power input is limited to 2400W, and continuous power output will be substantially less than this.
Figure 3 - Protection and Control Circuits
The control circuit need not be complex, but is very important. Although P33 could be used for DC detection, it would be better to use a dedicated circuit (which has not been designed yet). The thermal sensors can be transistors or dedicated ICs, and a simple comparator circuit detects that the temperature is above the trip value of 35°C to turn on the fans. The fans need to be high output types, as they will be called upon to dispose of a prodigious amount of heat when the amp is being pushed. Thermal switches act as a backup - if the fan controller fails to operate for any reason, normally open thermal switches will start the fans.
Water cooling is a viable option for an amp like this, especially for long term high power usage in a fixed location.
Construction
If you decide to build this amp, you will be prepared to spend a lot of money and time. You will also have sufficient experience to be able to work out the construction processes yourself. For a single channel, the parts alone will cost upwards of AU$1,000, probably closer to AU$1,500 or even more. Just the power transformer is likely to be around $250-300, and there's probably another $300 or more for filter capacitors. You will need a heatsink rated at about 0.03°C/W with forced cooling. I cannot suggest a suitable heatsink, but you can be sure that it will be large and expensive.
Please note that this project is provided as information only, and I will not provide any assistance to prospective builders. The entire project is your responsibility if you want to take it on.
Testing
If you are crazy enough to build this amp, then you will have sufficient skills to be able to work out what is needed to test it. Remember that the smallest mistake could easily despatch many expensive transistors, blow the tracks off a PCB, melt wiring, and all manner of other distasteful possibilities.
As with any high powered amplifier, initial testing should be done with a current limited power supply and no load. The amp will be functional with as little as ±10V or less, and the power supply and complete amplifier must be tested using a Variac (bypassing the soft start for initial tests). The Variac needs to be rated the same as the power transformer (i.e. at least 2kVA).
I will leave the remainder of the test procedure to the constructor, since the only people who should even attempt building an amp of this power should be very experienced with high power systems. If this does not describe you, then don't even think about it.

noreply@blogger.com (automation) — Thu, 21 May 2009 17:42:00 +0000

Starter kit of components

If you are new to electronics and would like to try adapting published projects, or designing and building your own circuits, you need to have a small stock of components available. However, there is a very wide range of components and it can be difficult to know which ones you really need! I hope the list below will help you choose a sensible selection which is within your budget. Remember that circuits built on breadboard can be dismantled after use and the components re-used.
It is usually cheapest to buy components by mail order and several suppliers are listed on the Links page. Send for a catalogue first, even if you have to pay for it, because most include a great deal of useful information as well as listing part numbers and prices. Kits of assorted components may be available and this is a great way to start if you can afford the initial cost. Remember that you will need to organise storage of the components!
stock a wide range of components and they have kindly allowed me to use their photographs on this page.
Essential componentsThese are the components used in most projects. The individual components are quite cheap, but the total cost of the set will be significant! One way to spread the cost is to add a few items from this list every time you buy the components for a particular project. Click on the titles for further information.
Resistors

0.25W carbon film resistors are the cheapest type. Choose ones with 4-band colour codes because these are easier to read (the precision of 5-band codes is unnecessary).Ideally you need a good selection of values over the range 100 to 1M such as the E6 or E12 series, but that is a large number of resistors! As a minimum I suggest: 470*, 1k*, 2k2, 4k7, 10k*, 22k, 33k, 47k, 100k, 220k, 470k and 1M. Buy at least 10 of each value and 20 of those marked *. The 470 resistors are for use with LEDs, even if a project specifies a slightly different value.
Resistors may be combined in series and parallel to obtain extra values, for example 100k and 220k in series is 320k which is close enough to 330k.
Capacitors

Low values: 0.01µF and 0.1µF metallised polyester, 10 of each.
High values: 1µF 63V, 10µF 25V, and 100µF 25V electrolytic with radial leads, 10 of each; 220µF 25V and 470µF 25V electrolytic with axial leads, 3 of each.
Diodes

1N4148 signal diode and 1N4001 rectifier diode, 5 of each.

LEDs

Red, yellow and green 5mm standard LEDs, 10 of each.

Transistors

About 5 general purpose, low power, NPN transistors. These should have a maximum collector current (Ic max) of 100mA, and a minimum current gain (hFE min) of 200. For example: BC548B (BC108 equivalent).
About 5 general purpose, medium power, NPN transistors. These should have a maximum collector current (Ic max) of 1A, and a minimum current gain (hFE min) of 30. For example: BC639 (BFY51 equivalent).
Integrated circuits ('chips') and holders
NE555 timer IC, at least 3 (10 if you plan to solder projects). It is not worth ordering other ICs at this stage unless you know they are needed for some of the projects you wish to try.
If you are planning to solder circuits on stripboard or PCB you will also need 8-pin, 14-pin and 16-pin DIL sockets (IC holders), at least 10 of each.
Variable resistors
Standard Variable ResistorPhotograph ©are cheaper than standard variable resistors but most have pins which are too large for breadboards. For breadboard circuits is is probably best to buy standard variable resistors and solder short single core 1/0.6mm wires onto them.
The useful values are: 10k LIN, 100k LIN and 1M LIN, buy 2 of each. A 1M LOG potentiometer is useful too. Knobs are optional because it is easy to turn the spindles by hand. If you buy presets the horizontal style are best, all presets are LIN.

PIC robotics: a beginner's guide to ... - Google Book Search

noreply@blogger.com (automation) — Fri, 15 May 2009 05:19:00 +0000

PIC rpicobotics: a beginner's guide to ... - Google Book Search

pic pograming

noreply@blogger.com (automation) — Fri, 08 May 2009 18:03:00 +0000

Fast Track to PIC Programming
You may know that when it comes to machines, programming is often used to tell the machine how to interact with its world. But have you ever wondered how this programming is actually physically implemented? One way is to use PICs (Programmable Interrupt Controllers). These chips allow you to write code that reads input signals, performs functions and sends signals to outputs based on conditions that you define. This tutorial will explain the basic process of writing programs for PICs and “burning” those programs to the device.
MOTIVATION AND AUDIENCE
The focus of this tutorial is to get you quickly acquainted with PICs so that you can start using them in your applications. As such, this tutorial will teach you how to:
Write code to define outputs.
Write code to read inputs and use those inputs to affect outputs.
Write code to react to a clock cycle.
“Burn” code into the device.
To do this, it is assumed that you already know how to:
Read an electrical schematic.
Construct and solder an electrical circuit onto a protoboard.
The rest of the tutorial is presented as follows:
Parts List and Sources
Construction
Programming
“Burning” Code Into A PIC
Final Words
PARTS LIST AND SOURCES
The majority of the parts will be required to construct a circuit to test your programs on. The parts listed in Table 1 are consumables used in the circuit:
TABLE 1
PART DESCRIPTION
VENDOR
PART
PRICE (2002)
QTY
PIC16F84-04/P
JAMECO
145111
5.95
1

40-PIN ZIF SOCKET
JAMECO
104029
10.95
1

PUSHBUTTON SWITCH
JAMECO
71642
1.49
1

8-POSITION DIP SWITCH
JAMECO
38842
0.79
1

4 MHZ CRYSTAL CLOCK OSCILLATOR
JAMECO
27967
1.89
1

0.1 UF CAP
JAMECO
151116
1.00 FOR BAG OF 10
1

0.1 INCH HEADERS
JAMECO
160881
0.39
1

SIPP 30-PIN WIREWRAP SOCKET
JAMECO
104053
1.95
1

T1-3/4 GREEN LED
JAMECO
104256
0.29
1

100 OHM RESISTOR

1

10 KILO OHM RESISTOR

1

220 OHM RESISTOR

9

3.3 KILO OHM RESISTOR

8

6 INCH PROTOTYPING CIRCUIT BOARD
RADIO SHACK
276-170
2.99
1

2-3/4 X 3-3/4 PROTOTYPING CIRCUIT BOARD
RADIO SHACK
276-158
2.39
1

The PIC we will be using (PIC16F84) was chosen because it is a very common PIC and because it can be programmed and reprogrammed without additional hardware (many PICs must be exposed to UV light to erase existing programs).
To construct the circuit, you will also need:
a soldering iron with a fine point
materials for soldering (solder, flux, etc.)
small gauge wire
wire strippers
multimeter
DC power supply
The items listed above can all be purchased from an electronics store such as Radio Shack. Some hardware such as Home Depot carry tools like wire strippers and multimeters.
There are many utilities for writing, compiling and burning PIC code. This tutorial uses the following software/hardware to program the PIC:
MPLAB for Windows (Microchip)
PICSTART Plus device programmer
The MPLAB software contains the text editor, compiler (MPASM) and device programmer software (PICSTART Plus) in a single program, thereby centralizing all your PIC programming needs. The book Easy Pic’n by David Benson is also an invaluable resource in learning how to use PICs. This tutorial refers to the book to clarify some of the code.
CONSTRUCTION
The circuit used to test your PIC programs is depicted in Figure 1.
Figure 1
This circuit is set up to test and display basic PIC functions. In this tutorial, Port B on the PIC (Pins 6- 13) is used as an output. LED’s are connected to all 8 of the Port B lines, and will light up when the line is set to a logic high, or ‘1’. Port A (Pins 17, 18, 1, 2 and 3) is used as an input. Its lines are connected to dip switches, which will set the line to a logic high when the switch is in the ‘On” position.
It is recommended that the LED and dip switch circuits be constructed on a separate board and connected to the PIC via a cable. This allows you to construct more complicated circuits in the future and easily switch between circuits.
A ZIF (Zero Insertion Force) socket is used to make repeated installation and removal of the PIC easy, and to help prevent the pins on the PIC from being damaged.
PROGRAMMING
What follows are a few sample codes that illustrate the functionality of the PIC. In each instance, the code will be given, followed by an explanation of how the code works.
Example 1: Outputting to LEDs
In this example you will learn how to define pins as output and how to set those pins to a logic hi or logic low. The following code sets pins corresponding to B0,B2,B4,B6 to a logic low and pins corresponding to B1,B3,B5,B7 to a logic hi.
outLed.asm

; FILE: outLed.asm
; AUTH: (Your name here)
; DATE: (date)
; DESC: Makes B0,B2,B4,B6 low and B1,B3,B5,B7 hi
; NOTE: Tested on PIC16F84-04/P.
; REFs: Easy Pic'n p. 23 (Predko p. 173 is bogus?)

list p=16F84
radix hex

;----------------------------------------------------------------------
; cpu equates (memory map)
myPortB equ 0x06 ; (p. 10 defines port address)
;----------------------------------------------------------------------

org 0x000

start movlw 0x00 ; load W with 0x00 make port B output (p. 45)
tris myPortB ; copy W tristate, port B outputs (p. 58)

movlw b'10101010' ; load W with bit pattern (p. 45)
movwf myPortB ; load myPortB with contents of W (p. 45)

circle goto circle ; done

end

;----------------------------------------------------------------------
; at burn time, select:
; memory uprotected
; watchdog timer disabled
; standard crystal (4 MHz)
; power-up timer on
In evaluating the code above, first and foremost it is important to realize that everything following a semicolon is a comment, and is ignored by the compiler. The actual code used by the compiler to program the PIC is shown below:

list p=16F84
radix hex

myPortB equ 0x06

org 0x000

start movlw 0x00
tris myPortB
movlw b'10101010'
movwf myPortB
circle goto circle
end
HEADER
The first portion of code is called the header. This information helps the compiler to format the code correctly. In our case, every header will be identical.
The first line

List p=16F84
describes the type of device that the program is to be burned to. The line

radix hex
tells the compiler what format numbers are in unless otherwise specified. In this case, the format is hexadecimal.
EQUATES
The next section of the program is called the equates. This is similar to variable declaration in other programming languages. Labels are assigned to addresses. Later, whenever that label is referred to in the program, the compiler looks up its address.
The line

portB equ 0x06
assigns ‘portB’ to the file register located at 0x06. Port B is always located at this file register.
ORG
In the line

org 0x000
org stands for origin. The org function has a few special uses, but this tutorial only uses the org statement as shown. When used in this manner, the org statement defines the beginning of the code.
INSTRUCTIONS
The next portion of code contains the actual instructions that tell the PIC what to do.

start movlw 0x00
This line is labeled as the start of the code. The function ‘movlw’ moves a literal (a number) to the file register W. You can not directly assign values to file registers. All values must first be passed through the W register.

tris myPortB
This command is outdated, though its still compatible with the version of software in use. The ‘tris’ command tells the compiler that the current W value will map the lines of the selected port as inputs or outputs (a ‘1’ in W means input, a ‘0’ in W means output).

movlw b'10101010'
This command moves the binary number ‘10101010’ to the W register.

movwf myPortB
The contents of the W register are now assigned to Port B, setting the appropriate pins as hi or low.

circle goto circle
This command labels the line of code as ‘circle’, and then refers bac to itself, thereby setting the program in a continuous loop.
END
Finally the compiler is told that it has reached the end of the code with an end statement.

end
All programs must have an end statement.
Example 2: Inputting from dip switches
Now that you have the fundamentals down, this program will illustrate how inputting is used to control outputs. In this example, all of the pins in port A are set as inputs (an should be connected to dip switches). When a dip switch is turned on, its value is passed to the corresponding output on port B, thereby lighting an LED.
Dip2Led.asm

; FILE: Dip2Led.asm
; AUTH: (Your name here)
; DATE: (date)
; DESC: Read Port A DIP switch and display on Port B LEDs
; NOTE: Tested on PIC16F84-04/P.
; REFs: Easy Pic'n p. 60

list p=16F84
radix hex

;----------------------------------------------------------------------
; cpu equates (memory map)
myPortA equ 0x05
myPortB equ 0x06 ; (p. 10 defines port address)
;----------------------------------------------------------------------

org 0x000
start movlw 0x00 ; load W with 0x00 make port B output (p. 45)
tris myPortB ; copy W tristate to port B outputs (p. 58)

movlw 0xFF ; load W with 0xFF make port A input
tris myPortA ; copy W tristate to port A

movf myPortA, w ; read port A DIP and store in W
movwf myPortB ; write W value to port B LEDs

circle goto start ; loop forever

end

;----------------------------------------------------------------------
; at burn time, select:
; memory uprotected
; watchdog timer disabled
; standard crystal (4 MHz)
; power-up timer on
This code is very similar to the previous code. Port B is declared as outputs in the same manner. In this case, port A is defined as inputs by the code

movlw 0xFF
tris myPortA
This fills the W register with 1’s, and uses those 1’s to declare port A as inputs. Instead of assigning a literal to port B, port A is read into the W register.

movf myPortA, w
This command says move the file register ‘myPortA’ into the W register. And as before, the contents of the W register are assigned to the LED’s at port B

movwf myPortB
The code is then told to return to the start and execute again.
Example 3: Reacting to a clock cycle
There is one other important functionality to the PIC that can be extremely useful. The PIC has a built in counter whose frequency is dependent upon the external oscillator in the circuit and upon certain options you set. These options along with the calculations for determining the frequency are explained below.
Clock.asm

; FILE: Clock.asm
; AUTH: (Your name here)
; DATE: (date)
; DESC: 1.0 - Internal timer, blink LED every 32.8 msec
; NOTE: Tested on PIC16F84-04/P.
; 4 MHz crystal yields 1 MHz internal clock frequency.
; "option" is set to divide internal clock by 256.
; This results in 1 MHz/256 = 3906.25 Hz or 256 usec.
; tmr0 bits 0 through 7 (255 decimal) is checked, thus yielding
; 255*256 usec = 65.28 msec delay loop
; REFs: Easy Pic'n p. 113

list p=16F84
radix hex

;----------------------------------------------------------------------
; cpu equates (memory map)
portB equ 0x06 ; (p. 10 defines port address)
tmr0 equ 0x01
;----------------------------------------------------------------------

org 0x000
start clrwdt ; clear watchdog timer
movlw b'11010111' ; assign prescaler, internal clock
; and divide by 256 see p. 106
option
movlw 0x00 ; set w = 0
tris portB ; port B is output
clrf portB ; port B all low
go bsf portB, 0 ; RB0 = 1, thus LED on p. 28
call delay
call delay
bcf portB, 0 ; RB0 = 0, thus LED off
call delay
call delay
goto go ; repeat forever

delay clrf tmr0 ; clear TMR0, start counting
again btfss tmr0, 0 ; if bit 0 = 1
goto again ; no, then check again
btfss tmr0, 1 ; if bit 1 = 1
goto again ; no, then check again
btfss tmr0, 2 ; if bit 2 = 1
goto again ; no, then check again
btfss tmr0, 3 ; if bit 3 = 1
goto again ; no, then check again
btfss tmr0, 4 ; if bit 4 = 1
goto again ; no, then check again
btfss tmr0, 5 ; if bit 5 = 1
goto again ; no, then check again
btfss tmr0, 6 ; if bit 6 = 1
goto again ; no, then check again
btfss tmr0, 7 ; if bit 7 = 1
goto again ; no, then check again
return ; else exit delay

end
;----------------------------------------------------------------------
; at burn time, select:
; memory uprotected
; watchdog timer disabled
; standard crystal (4 MHz)
; power-up timer on
The first thing notable about this code is a new equate

tmr0 equ 0x01
This is an 8 bit, read/write counter stored at this particular file register. In our case, the internal clock frequency is 1 MHz (external frequency gets divided by 4). This frequency can be further divided by setting a prescaler value (the value the internal frequency will be divided by). Based on the setting of 3 option bits, the prescaler value can be varied between 8 values ranging from 1 to 256. In our case, all 3 option bits are set, dividing the internal clock frequency by 256. This gives the frequency of the counter to be 1 MHz/256 = 3906.25 Hz. The next command

start clrwdt
Clears the watchdog timer and the prescaler value. The following commands

movlw b'11010111'
option
set the option bits. The significance of the option bits are as follows:
Bit Purpose
0 Prescaler Value
1 Prescaler Value
2 Prescaler Value
3 Prescaler Assignment (0=tmr0, 1=watchdog timer)
4 tmr0 external edge clock select (0=rising, 1=falling)
5 tmr0 clock source (0=internal instruction cycle, 1=external)
6 Interrupt edge select (0=falling, 1=rising)
7 Port B Pullup Enable (0=enabled, 1=disabled)
As you can see, in this code, the Prescaler bits are set to 111 (divide by 256), prescaler is sent to tmr0, tmr0 increments on the rising edge, the tmr0 source is the internal instruction cycle clock, interrupts occur on rising edges, and Port B pull-ups are disabled.
Proceeding through the code, the next portion defines Port B as outputs, as has been seen in previous examples. The code following that is the meat of this program.

go bsf portB, 0
call delay
call delay
bcf portB, 0
call delay
call delay
goto go
This loop turns an LED off and on repeatedly. First, the 0 bit in port B is set (made to logical hi). A delay subroutine is then called (explained later) to pause the program for a bit. The 0 bit is then cleared (made to logical low). The program is delayed once more, and then the process repeats. The new concept presented is that of a subroutine

delay clrf tmr0
again btfss tmr0, 0
goto again
btfss tmr0, 1
goto again
btfss tmr0, 2
goto again
btfss tmr0, 3
goto again
btfss tmr0, 4
goto again
btfss tmr0, 5
goto again
btfss tmr0, 6
goto again
btfss tmr0, 7
goto again
return
When delay is called, the program skips to this portion of the code. tmr0 (the counter) is first cleared (and then begins to count). The remaining code tests every bit in tmr0 to see if it is set to hi. If it isn’t, it returns to ‘again’. If it is set to hi, it skips the next line of code (“goto again”) and testes the next bit. This loop continues until the return statement is reached, in which case the subroutine is exited and the code proceeds from where delay was originally called. As can be seen, the delay subroutine will continue until all tmr0 bits equal ‘1’, or until tmr0 counts to 255.
“BURNING” CODE INTO A PIC
Now that you know how to write code, you need to know how to get your code into the PIC. The process of programming a PIC is often referred to as “burning”. To burn code into the PIC, we will be using the windows version of MPLAB.
In the MPLAB program, all the information about your program is stored in a project files. Project files contain information about the program, the device you’re using, one or more assembly language codes and compiled hex files. The process of burning a PIC contains three major steps. The first is to write the code in assembly language. Once the code is written, it must be compiled into a hex file for programming into the device. After successfully compiling the code, the final step is to program the device.
Begin by opening up the program MPLAB.
Create a new project by going to Project>New Project. In the new project dialogue box select a directory to place the project in and give the new project a name. When you’ve finished, click “Ok”.
You will now see the Edit Project dialogue box. Select the appropriate device, and set the development mode to MPLAB-SIM Simulator. In the project files window click the file that has the name of your file with a .hex extension. Click on the Node Properties button and in the window that appears, click “Ok”. This sets default node properties and allows you to add nodes later.
Exit the Edit Properties box by clicking “Ok”.
Now you may create assembly code. Got to File>New. A blank text editor box should appear. Enter your assembly code into this window. When you are done, save the code (File>Save, give the code a name and click “Ok”).
You must now assign the source code you just made to the project. Go to Project>Edit Project. In the Edit Project dialogue box, click the Add Node button. Browse to find the assembly code you just found. Select it and click “Ok”. The file name for the assembly code should now appear in the window. Click “Ok” to close the Edit Project box.
Now that the source code is associated with the project, its time to compile the code. Go to Project>Make Project. If the compile is successful, you will see the Build Results window appear with the message “Build completed successfully”. If there were errors they will be listed in the window. After compiling successfully, save the project (Project>Save Project).
The final step is to program the device. Select Picstart Plus>Enable Programmer. The Programmer Status dialogue box should appear. At this point, you should have the Picstart Plus device programmer plugged in and th serial cable connected to the serial port on your computer. Place the PIC in the ZIF socket with pin 1 in the top left corner, and lock it in place.
The most important part of this step is to ensure the configuration bits are set appropriately. If you noticed, at the end of each example code was a note indicating how the configuration bits should be set

; at burn time, select:
; memory uprotected
; watchdog timer disabled
; standard crystal (4 MHz)
; power-up timer on
Watchdog timer should be set to “off”, Oscillator should be set to “XT” (this is the setting for standard crystal), the memory setting should be set to “off” and the powerup timer should be set to “on”.
When the configuration bits are set correctly, click “Program” and wait for the programmer to finish. If the programmer completes successfully, your code is now in the PIC.
FINAL WORDS
After completing this tutorial you should be able program a PIC to send outputs, read inputs, and create functions using a clock. After creating a program in assembly code, you should be able to burn that program into the device for use in your application.
The concepts shown here were presented in relatively trivial situations. However, these concepts are fundamental to using PIC’s for larger, more complex applications.

eletronics industry

noreply@blogger.com (automation) — Fri, 24 Apr 2009 12:12:00 +0000

Acer
Acer Laboratories
Actel
Advanced Linear Devices
Advanced Micro Devices (AMD)
Alesis Semiconductor
Agilent Technologies
AKM Semiconductor
Allayer Communications
Allegro Microsystems
Alliance
Alpha Industries
Alpha Microelectronics
Alpha Semiconductor
Altera
American Microsystems
American Microsystems
ANADIGICs
Analog Devices
Analog Devices
Analog Systems
Anchor Chips
Apex Microtechnology
Apex Microtechnology
ARK Logic
Astec Semiconductor
ATecoM
ATI Technologies
Atmel
AT&T
AudioCodes
Aura Vision
Aureal
Austin Semiconductor
Avance Logic
Averlogic
Bel Fuse
Benchmarq Microelectronics
BI Technologies
Brooktree(now Rockwell)
Burr Brown
California Micro Devices
Calogic
Catalyst Semiconductor
Catalyst Semiconductor
C-Cube Microsystems
Centon Electronics
Cherry Semiconductor
Chips and Technologies (now Intel)
Chrontel
Cirrus Logic
ComCore Semiconductor
Conexant
Crystal (Cirrus Logic)
Cosmo Electronics
Cypress Semiconductor
Cypress Semiconductor
Cyrix Corporation
Daewoo Electronics Semiconductor
Dallas Semiconductor
Dallas Semiconductor
Dallas Semiconductor
Data Delay Devices
Davicom Semiconductor
Diamond Technologies
Diotec
DTC Data Technology
DTC Data Technology
DVDO
Elantec
Elantec
Electronic Designs(White Electronic Designs)
Electronic Technology
EG&G
Enhanced Memory Systems
Ensoniq Corp
Ericsson
ESS Technology
Exar
Exel Microelectronics (now Rohm)
Fairchild Semiconductor
Fuji Electric
Fuji Electric
Fujitsu
Fujitsu
Galileo Technology
Galvantech
GEC Plessey
General Electric (Harris)
General Instrument(General Semiconductor)
General Instrument(General Semiconductor)
General Semiconductor
Gennum
G-Link Technology
Gould (now AMI)
Harris (now Intersil)
Harris (now Intersil)
Hewlett Packard
HFO (VEB Halbleiterwerk Frankfurt/Oder, now BRD)
Hitachi
Holtek Microelectronics
Hualon Microelectronics
Hyundai
iC Designs(now Cypress)
iC-Haus
iC-Haus
I-Cube
IC Works
IGS Technologies
IMP
Impala Linear
Infineon Technologies
Information Storage Devices
Inmos(STMicroelectronics)
Integrated Circuit Designs
Integrated Circuit Systems
Integrated Device Technology (IDT)
Integrated Device Technology (IDT)
Integrated Silicon Solutions
Integrated Technology Express
Integrated Telecom Express
Intel
Intel
International Rectifier
Intersil
Intersil
Intersil
ITT (MicronasSemiconductor)
IXYS
Korea Electronics (KEC)
KOTA Microcircuits
Lansdale Semiconductor
Lansdale Semiconductor
Lattice Semiconductor
Lattice Semiconductor
Lattice Semiconductor
Level One Communications
LG Semicon
Linear Technology
Linfinity Microelectronics
Lite-On
Lucent Technologies
Macronix International
Marvell Semiconductor
Matra MHS
Matra MHS
Matra MHS
Matsushita Panasonic
Matsushita Panasonic
Maxim
Media Vision
Media Vision
Micro Electronics
Mikroelektronik Erfurt (formely DDR, now BRD)
Microchip Technology
Micro Linear
Micron Technology
Micronas
Micronix Integrated Systems
MicroPower Direct
Microtune
Mini-Circuits
Mitel Semiconductor
Mitsubishi
Monolithic Memories(now Vantis)
Mosaic Semiconductor
Mosel Vitelec
MOS Technologies
MoSys
Motorola
Motorola
M-Systems
Murata
Myson Technology
mwave (by IBM)
National Semiconductor
National Semiconductor
NEC
NEC
New Japan Radio (NJR)
NVidia Corporation
Oak Technology
OKI Semiconductor
OKI Semiconductor
Opti
Orbit Semiconductor
Oren Semiconductor
Performance Semiconductor
Pericom Semiconductor
PhaseLink Laboratories
Philips
PLX Technology
PMC-Sierra
PowerSmart
Princeton Technology
Precision Monolithics(Analog Devices)
QLogic
Qualcomm
Quality Semiconductor
Rabbit Semiconductor
Ramtron
Raytheon Semiconductor
Realtek Semiconductor
Rectron
Rendition
RCA Solid State(now Harris)
Rockwell
Rohm
S3
Sage
Sames
Samsung Electronics
Samsung Semiconductor
Sanken
Sanken
Sanyo
Sanyo
Scenix Semiconductor
SEEQ Technology
Seiko Epson Corp.
Seiko Epson Corp.
Seiko Instruments
Semelab (Magnatec)
Semtech
SGS-Ates(STMicroelectronics)
SGS(STMicroelectronics)
Sharp
Shindengen
Siemens (now Infineon)
Siemens (now Infineon)
Sierra (now PMS-Sierra)
Sigma Tel
Signal Processing Technologies
Signetics(now Philips)
Siliconians
Silicon Integrated Systems
Siliconix
Silicon Magic
Silicon Storage Technology
Silicon Systems(Texas Instruments)
Simtek Corporation
Sipex
SMC
Solid State Scientific(Thomson-CSF)
Sony
Space Electronics
Spectek
Standard Microsystems
Standard Microsystems
STMicroelectronics
Synergy Semiconductor(Micrel)
Synertek
Taiwan Semiconductor
TDK Semiconductor
Teccor Electronics
TelCom Semiconductor
Teledyne(TelCom Semiconductor)
Telefunken(now Vishay)
Teltone
Texas Instruments
Texas Instruments
Thomson-CSF
Toko America
Toshiba
Toshiba
Toshiba
Trident
TriQuint Semiconductor
Triscend
Tseng Labs
Tundra
United Microelectronics Corp (UMC)
United Technologies Microelectronics Center
Unitrode
USAR Systems
USAR Systems
Utron Technology
V3 Semiconductor
Vadem
Vanguard International Semiconductor
Vantis
Via Technologies
Virata
Vision Tech
Vitelic
VLSI Technology
Volterra
VTC
Waferscale Integration
Weitek(now Rockwell)
Western Digital
Western Digital
Winbond
Wolfsom Microelectronics
Xemics
Xicor
Xicor
Xilinx
Yamaha
Zetex Semiconductors
Zilog
Zilog
Zilog
Zilog
Zentrum Mikroelektronik Dresden
Zoran Corporation

NEW

noreply@blogger.com (automation) — Wed, 22 Apr 2009 08:53:00 +0000

using the 'cold plate' technique for cases where the inverter can be mounted directly onto a substantial heatsink. AC Tech Lenze 8200 vector inverters are available for power 0.55 to 90kW with three-phase supply. In the more popular smaller sizes up to 22kW, a space saving variant can reduce the requirement for panel space by up to 40%. By dissipating the heat outside the cabinet, these 'cold plate' versions enable panels to have higher enclosure ratings. Alternatively a plate with external cooling by liquid or air can be used.

(800) 894-0412 (208) 368-0415 (Fax)
info@clrwtr.com

Panasonic FP-X Series PLC
Matsushita Electric Works introduces the new ultra fast compact FP-X series Panasonic PLC after great success with the compact FP0 series Aromat NAIS PLC. The FP-X Panasonic PLC is set to redefine the industrial brick style PLC with new levels of expandability in a small robust package. The program capacity of 32 ksteps, exceeding the capacity of most compact Panasonic PLCs, can flexibly handle a wide variety of applications requiring future equipment expansion.

(800) 894-0412 (208) 368-0415 (Fax)
info@clrwtr.com

Sola SCP-X Series Power Supply
Sola Heavy Duty has introduced a new SCP-X field power supply that delivers 24Vdc power from an IP67-compliant package resistant to dust, water and other contaminants. Designed as a stand-alone unit that can be mounted directly to a machine, the SCP-X reduces end-user costs by eliminating the need for a separate cabinet and simplifying I/O device cabling. The metal outer case withstands physical abuse while efficiently dissipating heat to deliver consistent power from -40 to +60C.

(800) 894-0412 (208) 368-0415 (Fax)
info@ctiautomation.net

Panasonic CIMREX Touch Panels
The Cimrex Aromat NAiS touchscreens offer advanced TCP/IP network features that are very simple to set up. It is possible to network and monitor multiple panels through the internet or intranet. With this capability, you can edit both PLC and touch panel programs, change data points, monitor screens, transfer recipes, retrieve trend files or alarm data, send email, and create customized web pages for each panel. The CIMREX 91 is a large resistive Panasonic touchscreen.

(800) 894-0412 (208) 368-0415 (Fax)
info@clrwtr.com

RELECO Solid State Relays
TURCK Inc. announces the new C12 interfacer relay featured in the new "RELECO by TURCK" catalog. The 2-pole changeover contact relay is used for linking Xycom Industrial PC or IDEC PLC logic to machine operation. Releco C12 interfacer relays offer numerous advantages over conventional block, modular terminal strip or socket I/O products that require hours of wiring and potential downtime if a relay fails or needs to be replaced. The Releco relays also feature a built-in surge suppressor that eliminates the need to specify separate relays for AC and DC applications.

(800) 894-0412 (208) 368-0415 (Fax)
info@clrwtr.com

Entrelec ADO Terminal Blocks
ABB Low Voltage (Entrelec) has released a new family of terminal blocks that dramatically reduce installation times without compromising safety. Based on ABB's insulation displacement connection (IDC) technology, the new ADO system terminal blocks can reduce wiring times by up to 80% compared with conventional terminal blocks. The system eliminates the most common risks associated with connections, such as forgetting to strip the wire, folding over of wire strands, stripping too much wire, incorrect tightening torque or badly inserted terminal ends.

Mean Well launched two new product series to our AC/DC charger line, PB-300 & PB-360, 300-360W battery charger for lead-acid batteries that boost our charger product line up to 360W. Featuring optimal 3-stage charging characteristics and the automated derating capability for charging current under high ambient temperature, these intelligent Meanwell Power Supply will quickly and efficiently feed your hungry batteries and ensure the lifetime of them in the same time.

R58 Expert (R58E) sensors offer maintenance-free solid-state reliability for all color contrasts found in common product and material registration applications. Fast 50-microsecond sensing response produces excellent registration repeatability, even in ultra-high-speed applications. This fast response, coupled with the small 1.2 x 3.8 mm (0.05" x 0.15") sensing image, allows register marks to be made small and inconspicuous. R58E Banner Sensors feature TEACH mode sensitivity adjustment by presenting the output ON and output OFF sensing conditions to the sensor.

Idec Izumi is excited to announce our next generation of SmartRelays. Improvements include firmware, hardware and software upgrades, as well as a new expansion module. Idec Smart Relays continue to provide the same high quality you expect, while offering new features to save you even more time and money. Idec SmartRelays have always been a great value. The modular and adaptable base modules are equipped with 8 digital inputs and 4 digital outputs.

FIELD-EFFECT TRANSISTORS

noreply@blogger.com (automation) — Mon, 20 Apr 2009 18:35:00 +0000

FIELD-EFFECT TRANSISTORS
The field-effect transistor (FET) controls the current between two points but does so differently than the bipolar transistor. The FET operates by the effects of an electric field on the flow of electrons through a single type of semiconductor material. This is why the FET is sometimes called a unipolar transistor. Also, unlike bipolar semiconductors that can be arranged in many configurations to provide diodes, transistors, photoelectric devices. temperature sensitive devices and so on, the field effect is usually only used to make transistors, although FETs are also available as special-purpose diodes, for use as constant current sources. Current moves within the FET in a channel, from the source connection to the drain connection. A gate terminal generates an electric field that controls the current (see Fig 8.25). The channel is made of either N-type or P-type semiconductor material; an FET is specified as either an N-channel or P-channel device. Majority carriers flow from source to drain. In N-channel devices, electrons flow so the drain potential must be higher than that of the Source (VDS > O)- In P-channel devices, the flow of holes requires that VDS < name="jfet">..
JFETs (Junction Field Effect Transistors)
Junction Field Effect Transistors
JFET
There are two basic types of FET. In the junction FET (JFET), the gate material is made of the opposite polarity semiconductor to the channel material (for a P-channel FET the gate is made of N-type semiconductor material). The gate-channel junction is similar to a diode's PN junction. As with the diode, current is high if the junction is forward biased and is extremely small when the junction is reverse biased. The latter case is the way that JFETs are used, since any current in the gate is undesirable. The magnitude of the reverse bias at the junction is proportional to the size of the electric field that 11 pinches" the channel. Thus, the current
in the channel is reduced for higher reverse gate bias voltage.
Because the gate-channel junction in a JFET is similar to a bipolar junction diode, this junction must never be forward biased, otherwise large currents will ass p
through the gate and into the channel. For an N-channel JFET, the gate must always be at a lower potential than the source (Vcs < vgs =" 0)."> 0. For P-channel JFETs these conditions are reversed (in normal operation VGS 0 and the prohibited condition is when VGS < name="mosfet">..
MOSFETs (Metal Oxide Semiconductor Field Effect Transistors)
Enhancement Mode
Enhancement Mode
Depletion Mode
Depletion Mode
Metal Oxide Semiconductor Field Effect Transistors
MOSFET
Placing an insulating layer between the gate and the channel allows for a wider range of control (gate) voltages and further decreases the gate current (and thus increases the device input resistance). The insulator is typically made of an oxide (such as silicon dioxide, SiO2), This type of device is called a metal-oxide-semiconductor FET (MOSFET) or insulated-gate FET (IGFET). The substrate is often connected to the source internally. The insulated gate is on the opposite side of the channel from the substrate (see Fig ). The bias voltage on the gate terminal either attracts or repels the majority carriers of the substrate across the PN junction with the channel. This narrows (depletes) or widens (enhances) the channel, respectively, as VGS changes polarity. For N-channel MOSFETs, positive gate voltages with respect to the substrate and the source (VGS > 0) repel holes from the channel into the substrate, thereby widening the channel and decreasing channel resistance. Conversely, VGS < vgs =" 0." vgs =" 0;" name="biasing">..
Transistor Biasing
N-Channel MOSFET Depletion Mode
N-Channel MOSFET Enhancement Mode
N-Channel JFET
NPN BJT (Bipolar Junction Transistor)
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Power MOSFETs at Work in a Motor Controller using Pulse Width Modulation (PWM)

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