Electronic Projects

Amplifier BABY OF LYNX

noreply@blogger.com (Hendriono) — Wed, 28 Mar 2018 14:26:00 +0000

The introduction of this article should introduce an interesting construction of a relatively simple and quality NF amplifier, the second part describes the circuit solution and the principle of this amplifier's function. The following section is dedicated to the amplifier design itself and to the important calculations used in the amplifier design. The fourth part of the article contains instructions for amplifying the amplifier both with the use of recommended components and with the use of alternative parts. The following section lists the properties of the amplifier and its measurement results. The last part of the article contains photographs of the amplifier and its previous prototypes and, among other things, the basis for the construction.

Introduction

The design of the "Baby of Lynx" Amplifier is suitable in its basic version due to its not too complex complexity even for less experienced designers, but it is more focused on constructors. Among the main advantages of the amplifier are, in addition to its lower demands, also relatively small dimensions, which call for use in multichannel systems. Also, the construction of this amplifier is not expensive. Usually and today, it is practically not at all customary for these features to go hand in hand with the sound quality. That's what the amplifier can really surprise. Despite the low cost associated with its construction, the amplifier retains very low distortion and a large ratio between the useful signal and the noise. Excellent sound parameters are achieved, among other things, by the use of excellent ON signal transistors and high-end Toshiba end-to-line transistors designed specifically for audio amplifier applications. The audio parameters of the amplifier will satisfy even the most demanding listeners. Amplifier integration is very similar to legendary studio amplifiers such as Phase Linear, SAE, GAS or Revox. The amplifier scheme is based on the involvement of Jan Dupot, Danish designer, named Lynx Power Amplifier v. 2.2, as a non-commercial project for the general public. With his kind permission, I am introducing my version of the Amplifier called Baby of Lynx, which I spent a lot of time on editing and creating prototypes. And I not only believe that the amplifier will serve some designers for a long time and reliably and will be very happy with it. With regard to component selection, it is up to each reader to choose branded and high quality or less quality equivalents. However, I think that with a commercially available device, a functional and reliable amplifier can be built, the sound of which will sound very clearly and undisturbed even at higher volumes. At a relatively low cost, you can build an amplifier with dynamic sound, also applicable to studio conditions.

The design of the original Lynx 3 Amplifier was also supported by a well-known Czech designer of audio technique, Mr. Pavel Dudek. Here, the presented and edited version has been awarded with the SVOČ (Student Scientific Expertise) competition in the section "Electronics".

Background for construction

On this page you can download the Amateur Amplifier building of Baby of Lynx Amateur. It is quite possible that I will continue the project in the future and the amplifier will be modified, and to create a new version of the amplifier based on the structure published here. The building materials are freely available! FOR NON-COMMERCIAL USE !. If you are interested in "professional" PCBs as in the following photographs (coated holes, non-soldering mask) you can agree on their production by mail: hifiweb@seznam.cz. The PCB price will depend on the number of items requested and the total demand for PCB (max price approx. 300 CZK / piece).

Download for DIY

Coopper side: bottom.pdf
Component side: top.pdf
Mounting drawing: assembly.pdf
Component List: components.xls
Gerber files: gerber.rar

(Non-commercial use only!)

Site : http://hifi.czweb.org

F629 PIC Programmer

noreply@blogger.com (Hendriono) — Wed, 01 Dec 2010 18:16:00 +0000

The aim of the this programmer was principally to program the PIC 12F629. But as the PIC 12F675, PIC16F630 and PIC16F676 have same electrical and logical programming interface, I have extented the compatibility to these 3 PIC models.

Their are many PIC 12F629 very simple programmer but all required a separate power supply. The smarter ones are taking it from the PC through a USB connector. Though I wanted to get rid of this second connector to make the easiest programmer for the PIC12F629.

When using WxPic it is compatible with the JDM(2) adapter for serial port. Use this adapter selection to operate the F629 programmer.

F629 programmer

Schema

The F629 programmer Schema

The problem to solve for programming the PIC12F629 without external power supply is to build 2 supply voltages (+5 and +13V) and to be able to raise the +13V before the +5V. Most of the components in this schema are dedicated to this purpose.

To get 13V from the serial port it is not possible to use the ground of the interface as the 0V reference. It is necessary to use the negative voltage produced by the interface. So the VSS of the PIC will be set to -5V from the interface GND. This negative voltage is produced throught the PIC clamping diodes when the RTS (clock) or CTS (data) are brought down and regulated by Z1. The PIC12F629 clamping diodes accept up to 25mA wich is more that what the serial port can produce. Therefore, without installed PIC the supply voltage cannot be produced. C1 allows to keep the 5V while the clock and data are high.

The 13V is then easy to produce: TxD will be clamped to 8V by a 7.5V zener in serie with a diode. The diode is necessary to allow to drive TxD to VSS without being clamped to the ground by the direct current of the zener.

The PIC VDD cannot be connected directly to the ground because the PIC12F629 requires that 13V raises few microseconds before 5V. This means that during these microseconds VSS is -5V, GP3 (VPP) is +8V and VDD must be -5V. The role of Q1 is to connect VDD to the ground after VPP has raised. The few micro-second delay is obtained by C2 discharging. A FET transitor is necessary because the current though the VDD pin may go in both directions. Usually it enters in the PIC but when clock is high, its clamping generates a current output from VDD.

This VDD output clamping current is an issue when Q1 is blocked. It prevents VDD to stay low as it should, it could event raise the voltage on VDD higher than GND with a risk of overflow of maximum VDD. Q2 is dedicated to avoid this issue by disconnecting the clock input from RTS when Q1 is blocked.

Q3 is used to adapt the voltage range between the PIC data pin [-5V, 0] and the interface approximatively [-5V, 5V] in both direction. It is used in common based mode. The emitter and collector roles are reversed when it is the interface that drives the data.

R2 is used as a pull up when the PIC drives the data, and transmits the signal in the other direction. To improve the signal quality that must reach -5V at low level, D2 limits the loss of negative voltage that may occur through R2. It helps when the interface has a limited voltage range. But it may be omitted with a compliant RS232 interface.

Printed Circuit Board

The F629 programmer PCB viewed from copper side

The F629 programmer parts viewed from component side

The figures above describe the PCB for the programmer. To print these document in actual size the following pdf files should be used. Note that the PCB in the pdf is provided viewed from the component side. This allows to print it and used the printed sheet as a mask with the printed ink touching the photosensible coat.

The main copper area is connected to the ground. Remember that this ground is not the PIC VSS. As you can see I like to maximize the ground plan. Though this is not a high frequency device that would require a ground plan, I reduce the use of ferric chloride.

Note that the PIC socket is mounted on the copper side. The 5 pins that must be soldered have a large pad outside of the circuit to help that operation. A 14-pin socket is used, though the PIC12F629 needs only 8, to accomodate properly the PIC16F630 and PIC16F676. Take care to mount the socket in the right direction in order that you get the right indication of the PIC mounting direction. The half circle on the PCB should help you to find the right direction.

The mounting of the PIC must always put the Pin1 in socket's pin 1, for a 8-pin or 14-pin PIC.

Mounting

To fit in a small box the components have to be mounted close to the board. The transistors must be inserted the closest as possible. The electrochemical capacitor has to be laid on the reserved place.

The mounting of the components

The soldering is easy except for the integrated circuit socket. I have reused an old socket that has the advantage to be fixed with 2 screws diam 2mm. This avoids to force on the soldering when inserting and especially removing the PIC while soldering on the copper side reduces the resistance of the assemblage.

The socket on soldering side

The indications on the PCB should help you when soldering the cable coming from the DB9 (the higher mistake risk in this realisation is there). To help again in this direction below is the DB9 RS232 pinout for our 5 signals viewed as you will see it when you will solder the wires to the pins (either the front view of the male connector or the rear view of the female connector).

The RS232 DB9 connector from the rear of the female connector

Original Source : WxPIC

Download Software :
WxPic installer for Windows (XP, VISTA or 7) V1.2.1R194 dated 2010-01-15 (1410754 bytes)

Automotive LED Timing Light

noreply@blogger.com (Hendriono) — Wed, 17 Nov 2010 18:47:00 +0000

A useful timing strobe can be constructed using high-brightness LEDs and a few common components. Ignition pulses from the number 1 cylinder high-tension lead are used to trigger the circuit via a home-made inductive pickup.

Transistors Q1 & Q2 buffer and amplify the pulses from the pickup, which then drive the inputs of three Schmitt-trigger inverters (IC1a, IC1c & IC1f). Each positive pulse at the inverter inputs causes a low pulse at their outputs, forward-biasing D2 and immediately discharging the 6.8nF capacitor.

Schematic Automotive LED Timing Light

When the capacitor is discharged, the inputs of the second bank of three inverters (IC1b, IC1d & IC1e) see a logic low level, so their outputs go high, driving Q3 into conduction and powering the LED array.

After the pulse ends, the IC1a, IC1c & IC1f inverter outputs return high, reverse biasing D2. However, it takes some time for the 6.8nF capacitor to charge to the logic high threshold voltage of the inverters’ inputs, effectively stretching the initial pulse width and lighting the LEDs for the required amount of time.

The pickup can be salvaged from an old Xenon timing light or made up from a "C" type ferrite or powered iron core large enough to fit around a HT lead. Some experimentation will be required to determine the number of turns required to achieve reliable triggering. About 100 turns of light-gauge wire proved sufficient on the prototype.

A cleat is used to close the magnetic path around the lead and is held in place with a large battery clip. Miniature screened microphone cable can be used to connect the pickup to the circuit, to prevent interference from other sources. Refer to the Current Clamp Adapter project in the September 2003 issue of SILICON CHIP for more ideas on how to make the core and clamp assembly.

Author: K. J. Benic
Source : Silicon Chip, Issue 200, 19 May, 2005

Inverter for Soldering Iron

noreply@blogger.com (Hendriono) — Tue, 09 Nov 2010 18:00:00 +0000

Here is a simple 12 V inverter for using a small soldering iron (25W, 35W, etc) in the absence of mains supply. It uses eight transistors and a few resistors and capacitors. Transistors T1 and T2 (each BC547) form an astable multivibrator that produces 50Hz signal. The complementary outputs from the collectors of transistors T1 and T2 are fed to pnp Darlington driver stages formed by transistor pairs T3-T5 and T4-T6 (utilising BC558 and BD140). The outputs from the drivers are fed to transistors T7 and T8 (each 2N3055) connected for push-pull operation. Use suitable heat-sinks for transistors T5 through T8.

A 230V AC primary to 12V-0-12V, 4.5A secondary transformer (X1) is used. The centre-tapped terminal of the secondary of the transformer is connected to the battery (12V, 7Ah), while the other two terminals of the secondary are connected to the collectors of power transistors T7 and T8, respectively.

When you power the circuit using switch S1, transformer X1 produces 230V AC at its primary terminal. This voltage can be used to heat your soldering iron. Assemble the circuit on a general purpose PCB and house in a suitable cabinet. Connect the battery and transformer with suitable current-carrying wires. On the front panel of the box, fit power switch S1 and a 3-pin socket for connecting the soldering iron.

Soldering Iron Voltage Inverter Circuit Diagram

Source [C I R C U I T L A B]

Soldering Fundamentals

noreply@blogger.com (Hendriono) — Tue, 09 Nov 2010 17:11:00 +0000

Safety precautions

Never touch the element or tip of the soldering iron. They are very hot (about 600°F) and will give you a nasty burn.
Always return the soldering iron to its stand when not in use. Never put it down on your workbench, even for a moment!
Work in a well-ventilated area. The smoke formed as you melt solder is mostly from the flux and quite irritating. Avoid breathing it by keeping your head to the side of, not above, your work.
Wash your hands after using solder. Solder contains lead which is a poisonous metal.

Preparing the soldering iron

Place the soldering iron in its stand and plug in. Set the knob on the soldering iron station to a starting level of 4. The iron will take a few minutes to reach its operating temperature of about 600°F.
Dampen the sponge in the stand. It should be damp, not dripping wet.
Wait a few minutes for the soldering iron to warm up. You can check if it is ready by trying to melt a little solder on the tip.
Wipe the tip of the iron on the damp sponge. This will clean the tip.
Melt a little solder on the tip of the iron. This is called 'tinning' and it will drastically help the heat to flow from the iron's tip to the joint. If it seems to be taking a long time for a joint to heat up it is most likely because the tip is not tinned.

Inserting the component

Bend the leads of the component to fit in the holes in the board if necessary.
Insert the component into the board. IMPORTANT make absolute sure that the component you are placing is in the correct location and the correct orientation. Some of the components must be soldered in a certain orientation in order to function.
If possible, bend the leads of the component outward once they are inserted into the board. This will keep the component from falling out if you turn the board upside-down.

You may wish to place many components consecutively, and then solder them all. This will save you time.

How to solder

Hold the soldering iron on the rubber handle like a pen. NEVER touch the hot metal element or tip.
Touch the tip of the tinned soldering iron onto the joint to be soldered. Make sure it touches both the component lead and the track. Hold the tip there for a moment.
Feed a little solder onto the joint.
- Apply the solder to the joint, not the iron.
- Solder should flow smoothly onto the lead and track to form a volcano shape as shown in the diagram. The track and lead should literally suck up the solder.
- If the solder balls up and does not seep into the joint, allow more time for the joint to heat until you see the solder flow or seep into the joint. Do not add more solder.
Remove the solder wire, then the iron, while keeping the joint still. Allow the joint a few seconds to cool before you move the circuit board.
Trim any long leads sticking out the bottom of the board.
Inspect the joint closely.
- The joint should look shiny and have a 'volcano' shape.
- If the joint has a dull texture, you will need to reheat it and feed in a little more solder. This time ensure that both the lead and track are heated fully before applying solder. Also, make sure not to move the lead while the joint is solidifying.
- If the solder looks like a blob you will need to either reheat the solder so that it may bond completely with the joint, or if there is just too much solder on the joint you may need to remove some solder using a desoldering device.

Note: With practice and an iron set at the correct temperature, you should be able to solder a joint every one to two seconds.

This is how you should position the solder and the iron when making the joint:

A good Joint should look like this:

If the joint is dull or bulged, remelt the solder:

Source [Cal Poly Robotics Club]

PIC and EEPROM Programmer

noreply@blogger.com (Hendriono) — Sun, 07 Nov 2010 16:02:00 +0000

PIC and EEPROM Programmer

In this project we are building a JDM programmer that can handle PIC12, PIC16 and PIC18 family microcontrollers and some popular 24C family EEPROMs. The programmer also provides ICSP feature that allows In-Circuit Serial Programming. So if you desire, you will not have to carry your MCU each time when you reprogram it. The circuit is connected to the PC via serial port and no external power supply is needed. On the other hand, if you want to use it with a laptop that do not provide RS232 connection, using the circuit with a USB to RS232 converter may not give a proper result.

Supported Devices

EEPROM:

24C01A, 24C02, 24C04, 24C08, 24C16, 24C32, 24C64/65, AT24C128, AT24C256, AT24C512, M24C128, M24C256, 24C515, PCF8572 or 8572 = 24C01, PCF8582 or 8582 = 24C02, PCF8592 or 8592 = 24C04, SDA2506, SDA2516, SDA2526, SDA2546, SDA2586, SDA3506, SDA3516, SDA3526, 4C016 == 24C01, GRS-003 == 24C02, GRN-004 == 24C04, GRN-008 == 24C04, GRX-006 == 24C04, GRX-007 == 24C04, KKZ06F == 24C01, BAW658049 == 24C02, BAW57452 == 24C02, M8571 == 24C02, X24C0

Microchip PIC:

12C508, 12C508A, 12C509, 12C509A, 12CE518, 12CE519,12C671, 12C672, 12CE673, 12CE674,12F629, 12F675, 16C433, 16C61, 16C62A, 16C62B, 16C63, 16C63A, 16C64A, 16C65A, 16C65B, 16C66, 16C67,16C71, 16C72, 16C72A, 16C73A, 16C73B, 16C74A, 16C74B, 16C76, 16C77,16F73, 16F74, 16F76, 16F77,16C84, 16F83, 16F84, 16F84A, 16C505,16C620, 16C620A, 16C621, 16C621A, 16C622, 16C622A, 16CE623, 16CE624, 16CE625, 16F627, 16F628, 16F628A, 16F630, 16F676, 16C710, 16C711, 16C712, 16C715, 16C716, 16C717, 16C745, 16C765, 16C770, 16C771, 16C773, 16C774, 16C781, 16C782, 16F818, 16F819, 16F870, 16F871, 16F872, 16F873, 16F874, 16F876, 16F877, 16F873A, 16F874A, 16F876A, 16F877A, 18F242, 18F248, 18F252, 18F258, 18F442, 18F448, 18F452, 18F458, 18F1320, 18F2330, 18F432

Building the Programmer
As you see the circuitry contains a few components listed below.
Component List

T1, T2 : BC337 Transistor
D1, D4, D5, D6 : 1N4148 Diode
D3 : 6V2 Zener Diode
D2 : 5V1 Zener Diode
R3, R4 : 1K8 1/4W Resistor
R1 : 10K 1/4W Resistor
R2 : 1K5 1/4W Resistor
X1 : DB9 PCB Mount Female Connector
C1, C2 : 100uF 16V Electrolytic Capacitor
SV1 and SV4 : 40 Pin Machine Tooled IC Socket
SV2, SV3 : 20 Pin Machine Tooled IC Socket
SV5 (ICSP) : 6 Pin Header Connector9
L1, L2, L3 : LED (L1: GREEN, L2: RED, L3: YELLOW)

PIC and EEPROM Programmer Components

The PCB file is provided in pdf format. You can apply it to the board by using the ironing method.

Click here to download the schematic and the PCB layout files.

PIC and EEPROM Programmer Printed Board

Assembling the components is straightforward. The only trick is shown in the photo. Before soldering the 40 pin socket, you must cut the plastic bridges between the sides. Another issue, don't forget to solder the diode (D6) and the jumper under the sockets first.

PIC and EEPROM Programmer Cutting the Socket

Here is the final. If you don't miss any short-circuits, you will see the red LED will bright up when you connect the programmer to the serial port. Now it is ready to use. You may use ICPROG and WinPIC to start programming your PICs or EEPROMs.

LED Indications; Yellow:Clock , Red:Power , Green:Program

PIC and EEPROM Programmer

Placement
Placement is shown in the figure below.
Don't forget! Wrong placement may defect your IC, programmer or computer.
You may use a ZIF socket instead according to your needs.

PIC and EEPROM Programmer Placement

PIC and EEPROM Programmer : [Original Link]

USB Printer Share Switch Circuit Project

noreply@blogger.com (Hendriono) — Fri, 29 Oct 2010 14:36:00 +0000

This simple device allows two computers to share a single USB printer or some other USB device, such as an external flash drive, memory card reader or scanner. A rotary switch selects the PC that you wish to use with the USB device, while two LEDs indicate the selected PC.

The most common way to share a USB printer between two PCs is to use one machine as a print server. However, that’s not always convenient because it means that the server PC must always be on if you want to print something.

Final Result

That can be a real nuisance if you just want to quickly fire up the other machine and print something out. It also means that the two PCs must be networked together, either via a hub/router or directly via an ethernet crossover cable.

Another way is to use a dedicated USB print server. However, as before, this must be connected to an ethernet network, along with the PCs. Such devices also need their own power supply, generally cost well over $100 and are overkill if you just want to share a single USB printer between two computers for occasional printing in a home set-up.

Parts Layout

That’s where this simple device comes in. It’s basically a 2-way switch box that lets you manually switch your USB printer from one PC to the other, as required. The switching is performed using a rotary switch, while two LEDs on the front panel indicate which PC has been connected to the printer.

This method has several advantages. First, you don’t need to network your two computers. Second, you can print from either machine with the other turned off. And third, the device doesn’t need a power supply.

Circuit Diagram

The circuit uses switch poles S1a-S1c to select either USB socket CON1 or CON2 and connect its pins through to CON3. The fourth pole (S1d) selects either LED1 or LED2, to indicate which PC has been selected.

Source: Silicon Chip14 April 2009

Studio Stereo Headphone Amplifier

noreply@blogger.com (Hendriono) — Fri, 29 Oct 2010 14:24:00 +0000

Here's a top-class headphone amplifier that can drive high or low impedance 'phones to full power levels, with very low noise and distortion. For best performance, it can be teamed with the Stereo Preamplifier described last month. Alternatively, it can be used as a standalone unit, requiring only a power supply and a volume control pot for use with any line-level signal source (CD/MP3 player etc). It even includes dual outputs, so you can listen with a friend!

Final Result

Many of our high-power audio amplifier designs already provide an output for headphones. The additional circuitry required for headphone support is simple; just two resistors in series with the loudspeaker outputs to limit the drive current and protect the ’phones in the case of amplifier failure.

Considering its simplicity, this resistive limiting scheme works well, although it will cause distortion if the load is non-linear – a likely prospect with most headphones. Apart from eliminating this potential source of distortion, there are a number of other reasons why you might consider building a separate headphone amplifier.

For a start, not everyone owns a pair of top-rated headphones or even a high-performance power amplifier. After all, an amplifier that equals or betters the performance of this new headphone amplifier will set you back more than a few shekels!

Parts Layout

Another reason might be for use with the latest "high-tech" audio electronics gear. The headphone outputs in much of this gear cannot drive low-impedance ’phones – or at least not to decent listening levels. In addition, available output power in portable devices is deliberately limited to conserve battery energy. This means that lots of distortion might be present at higher listening levels, even with sensitive headphones.

One way around this is to feed the line-level outputs of this gear into your power amplifier and then plug your low-impedance headphones into that. That works but then you’re tethered to an immovable object. Besides, the power required to drive headphones is around 1/1000th of that required to drive loudspeakers, so a large power amplifier could be considered a tad oversized for the job!

Circuit Diagram

Features & Performance

Main Features:

High performance – very low noise & distortion
Drives high and low-impedance headphones
High output power (up to 200mW; into 8Ω and 32Ω)
Dual headphone sockets – can drive two pairs!
Works with a preamp or any line-level audio source

Measured Performance:

Frequency response : flat from 10Hz to 20kHz (see graphs)
Rated output power : 200mW into 8Ω and 32Ω, 85mW into 600Ω
Max. output power (current or voltage limited) : 575mW into 8Ω, 700mW into 32Ω, 130mW into 600Ω
Harmonic distortion : typically .0005% (600Ω load),.001% (32Ω load) and .005% (8Ω load)
Signal-to-noise ratio (A-weighted) : -130dB (600Ω), -120dB (32Ω) and -111dB (8Ω) with respect to 100mW output power.
Channel crosstalk : better than -68dB from 20Hz-20kHz at 100mΩ output power
Input impedance : ~47kΩ || 47pF
Output impedance : ~5Ω

Note:

All tests were performed with the amplifier driven from low source impedance. For crosstalk measurements, the non-driven input was back-terminated into 600Ω.

CAUTION!

Continual exposure to very high noise levels (including loud music) will cause hearing loss and can cause tinnitus. Hearing loss is cumulative, gradual and almost symptomless!

Source: Silicon Chip 28 November 2005

Build Your Own Recorder PICS!

noreply@blogger.com (Hendriono) — Sun, 24 Oct 2010 06:26:00 +0000

For all you ever wanted to schedule your family pics Microchip and had no time, money or lack of resources, now is the time to do it! With a few simple patterns of PCB and some simple and inexpensive electronic materials, you can build your own recording of PICs connected by serial port to your PC and you can start to burn Pic's like crazy!

The Materials

D1 a D6 ------------------------- 1N4007
C1 ------------------------------ 2200uf/25V
C2 ------------------------------ 0,47uf/100V
C3 ------------------------------ 0,1uf/50V
C4 ------------------------------ 10uf/50V
IC1 ----------------------------- LM7812C
IC2 ----------------------------- L7805
IC3 ----------------------------- SN74LS07
R1, R2, R3, R4, R7, R8 ---------- 10k
R5, R6, R10 --------------------- 1k
R9 ------------------------------ 470R
Q1, Q2 -------------------------- BC557
DB9 female connector for board
Conector DB9 Macho con tapa DB9 Male with lid
Conector DB25 Macho con tapa DB25 Male with lid
Transformer 12 to 15V / 0.5 A

Here, two schemes PCB assembly:

And the scheme of connection to the serial port:
The recorder supports a wide range of pics of 18 and 8-pin:
18 pin type 16C6X, 16C7X, 16C8X, 16F8X, and the PIC's 8-pin 12C50X

Original source : Brico Geek

ZenitPCB - Free PCB Layout

noreply@blogger.com (Hendriono) — Sun, 24 Oct 2010 04:08:00 +0000

ZenitPCB Layout is an excellent tool to create professional printed circuit board ( PCB ). It is a flexible easy to use CAD program, which allow you to realize your projects in a short time.

ZenitPCB Layout is completely freeware for personal or semi-professional use, limited to 800 pins, that is the border line, between the hobby and professional jobs.

With ZenitPCB Layout is possible to create the project starting both from the schematic capture or by the layout itself.

In the first instance you can import a netlist (file ASCII containing electrical info) from different schematic capture ( Orcad®, Pads®, Multisim®, Protel®, Eagle®....), whit all the components and the relative electrical connections (net).

In the second instance, you can realize your project directly from the layout editor, importing components from the library and connect the pins directly with the cursor (auto ratlines).

It is, therefore, possible to create a board without import a netlist from Schematic capture.

ZenitPCB Layout has all the need to achieve a good printed circuit board, is singleside both doubleside, using the rules of individual project or general, through the net class.

Feature:

ZenitCapture Schematic is easy to learn and fast to use. Schematic designs can be created quickly using the easy-feature toolset available. A schematic is a sketch of an electrical logic. It contains the electrical connection between component symbols by the use of signal wires. A schematic in ZenitCapture can have several pages and can be lead to a layout by a Netlist File (ASCII).
ZenitPCB Layout is an excellent tool to create professional printed circuit board ( PCB ). It is a flexible easy to use CAD program, which allow you to realize your projects in a short time.
Now, for more control of the project, you can review the gerber created, through the viewer ZenitPCB GerberView

Source:
Klick here for more information about ZenitPCB

12V Speed Controller/Dimmer

noreply@blogger.com (Hendriono) — Fri, 22 Oct 2010 17:53:00 +0000

This handy circuit can be used as a speed controller for a 12V motor rated up to 5A (continuous) or as a dimmer for a 12V halogen or standard incandescent lamp rated up to 50W. It varies the power to the load (motor or lamp) using pulse width modulation (PWM) at a pulse frequency of around 220Hz.

SILICON CHIP has produced a number of DC speed controllers over the years, the most recent being our high-power 24V 40A design featured in the March & April 2008 issues. Another very popular design is our 12V/24V 20A design featured in the June 1997 issue and we have also featured a number of reversible 12V designs.

Final Project

For many applications though, most of these designs are over-kill and a much simpler circuit will suffice. Which is why we are presenting this basic design which uses a 7555 timer IC, a Mosfet and not much else. Being a simple design, it does not monitor motor back-EMF to provide improved speed regulation and nor does it have any fancy overload protection apart from a fuse. However, it is a very efficient circuit and the kit cost is quite low.

Parts Layout

Connection Diagram

There are many applications for this circuit which will all be based on 12V motors, fans or lamps. You can use it in cars, boats, and recreational vehicles, in model boats and model railways and so on. Want to control a 12V fan in a car, caravan or computer? This circuit will do it for you.

Circuit Diagram

The circuit uses a 7555 timer (IC1) to generate variable width pulses at about 210Hz. This drives Mosfet Q3 (via transistors Q1 & Q2) to control the speed of a motor or to dim an incandescent lamp.

Halogen Lamps

While the circuit can dim 12V halogen lamps, we should point out that dimming halogen lamps is very wasteful. In situations where you need dimmable 12V lamps, you will be much better off substituting 12V LED lamps which are now readily available in standard bayonet, miniature Edison screw (MES) and MR16 halogen bases. Not only are these LED replacement lamps much more efficient than halogen lamps, they do not get anywhere near as hot and will also last a great deal longer.

Source: Silicon Chip 15 November 2008

PIC Controlled Relay Driver

noreply@blogger.com (Hendriono) — Fri, 22 Oct 2010 17:34:00 +0000

This circuit is a relay driver that is based on a PIC16F84A microcontroller. The board includes four relays so this lets us to control four distinct electrical devices. The controlled device may be a heater, a lamp, a computer or a motor. To use this board in the industrial area, the supply part is designed more attentively. To minimize the effects of the ac line noises, a 1:1 line filter transformer is used.

The components are listed below.

1 x PIC16F84A Microcontroller
1 x 220V/12V 3.6VA (or 3.2VA) PCB Type Transformer (EI 38/13.6)
1 x Line Filter (2x10mH 1:1 Transformer)
4 x 12V Relay (SPDT Type)
4 x BC141 NPN Transistor
5 x 2 Terminal PCB Terminal Block
4 x 1N4007 Diode
1 x 250V Varistor (20mm Diameter)
1 x PCB Fuse Holder
1 x 400mA Fuse
2 x 100nF/630V Unpolarized Capacitor
1 x 220uF/25V Electrolytic Capacitor
1 x 47uF/16V Electrolytic Capacitor
1 x 10uF/16V Electrolytic Capacitor
2 x 330nF/63V Unpolarized Capacitor
1 x 100nF/63V Unpolarized Capacitor
1 x 4MHz Crystal Oscillator
2 x 22pF Capacitor
1 x 18 Pin 2 Way IC Socket
4 x 820 Ohm 1/4W Resistor
1 x 1K 1/4W Resistor
1 x 4.7K 1/4W Resistor
1 x 7805 Voltage Regulator (TO220)
1 x 7812 Voltage Regulator (TO220)
1 x 1A Bridge Diode

The transformer is a 220V to 12V, 50Hz and 3.6VA PCB type transformer. The model seen in the photo is HRDiemen E3814056. Since it is encapsulated, the transformer is isolated from the external effects. A 250V 400mA glass fuse is used to protect the circuit from damage due to excessive current. A high power device which is connected to the same line may form unwanted high amplitude signals while turning on and off. To bypass this signal effects, a variable resistor (varistor) which has a 20mm diameter is paralelly connected to the input.

Another protective component on the AC line is the line filter. It minimizes the noise of the line too. The connection type determines the common or differential mode filtering. The last components in the filtering part are the unpolarized 100nF 630V capacitors. When the frequency increases, the capacitive reactance (Xc) of the capacitor decreases so it has a important role in reducing the high frequency noise effects. To increase the performance, one is connected to the input and the other one is connected to the output of the filtering part.

After the filtering part, a 1A bridge diode is connected to make a full wave rectification. A 2200 uF capacitor then stabilizes the rectified signal. The PIC controller schematic is given in the project file. It contains PIC16F84A microcontroller, NPN transistors, and SPDT type relays. When a relay is energised, it draws about 40mA. As it is seen on the schematic, the relays are connected to the RB0-RB3 pins of the PIC via BC141 transistors. When the transistor gets cut off, a reverse EMF may occur and the transistor may be defected.

To overcome this unwanted situation, 1N4007 diodes are connected between the supply and the transistor collectors. There are a few number of resistors in the circuit. They are all radially mounted. Example C and HEX code files are included in the project file. It energizes the next relay after every five seconds.

Click here to download the schematics, PCB layouts and the code files

Source : circuit-projects.com

LAN RJ45 Cable Connection Tester

noreply@blogger.com (Hendriono) — Wed, 20 Oct 2010 16:55:00 +0000

Here's a very simple, but practical circuit, which is used to check the type of LAN cables (straight or cross) as well as possible faults. So we use a unit that has 8 outputs, each one of which produces a pulse successivly. Only one output can be high at any time. Then we use two rj45 connectors and we apply the pulses to the 8 pins of one connector (A) wnd we connect LEDs at the pins of the other connector (B). If we connect a straight LAN cable, we notice that the LEDs glow one by one successively. If a wire is broken, the coresponding LED will not glow. Just watch the LEDs. If we connect a cross wire, then the order of LEDs glowing changes to 1,2,7,4,5,8,3,6. So we can laber the LEDs in that order, so that we can watch easily.

If both ends of the cable are not close enough to be pluged onto the curcuit, we can use an remote board, which has only one rj-45 connector and 8 LEDs. Then plug one end of the cable to connector A on main board and connect the other end to the remote unit. Notice that no common wire is needed for the remote unit.

I have included an alternative circuit instead of using classic ics, I use the AVR ATtiny2313, but any AVR controller can be easily adapted. See photo and diagram.

Thank you
Vasilis Stergiopoulos

Credit:

Merlin PCB Designer

noreply@blogger.com (Hendriono) — Tue, 19 Oct 2010 15:00:00 +0000

General information

Merlin PCB Designer is a free printed circuit board (PCB) layout tool that is distributed by Falco Systems. Whether you are professionally involved with printed circuit manufacturing, or you are just making a few PCBs for your job or at home, Merlin PCB Designer can make your life easy and save you a significant part of your PCB-related expenses.

Falco Systems Merlin PCB Designer

If you already have CorelDRAW on your computer, you can use the licence-free Merlin PCB Designer package to convert it into a powerful PCB layout tool. Bu sure to read the manual first!

Download Merlin PCB Designer

Merlin PCB Designer comes as a zip file with CorelDRAW scripts (from version 7 to 11), and a large component library + manual. To download Merlin PCB Designer, please click on the links below.

Baby Lynx - Power Amplifier

noreply@blogger.com (Hendriono) — Mon, 18 Oct 2010 13:55:00 +0000

On this page you can download materials for the construction of an amateur amplifiers Baby of the Lynx. It's a pretty good chance that the project will pay in the future and will modify the amplifier and the emergence of a new version of the amplifier based on currently published here structures. Materials for construction shall be freely distributable! FOR NON-COMMERCIAL USE!. If interested in "professional" in the PCB design as the photos below (plated holes, solder mask) can agree on their production mail: hifiweb@seznam.cz. DPS Price will depend on the number of demanded items and the total demand of PCB (max price 300 CZK / piece).

Source for download:

Page links: bottom.pdf
Page elements: top.pdf
Filling drawing: assembly.pdf
List of components: components.xls
Gerber files: gerber.rar

(Non-commercial use only!)

For more information please visit George

USB Power Injector For External Hard Drives

noreply@blogger.com (Hendriono) — Mon, 18 Oct 2010 13:38:00 +0000

A portable USB hard drive is a great way to back up data but what if your USB ports are unable to supply enough "juice" to power the drive? A modified version of the Silicon Chip Usb Power Injector is the answer. For some time now, the author has used a portable USB hard drive to back up data at work. As with most such drives, it is powered directly from the USB port, so it doesn’t require an external plug pack supply.

Project's Picture

In fact, the device is powered from two USB ports, since one port is incapable of supplying sufficient current. That’s done using a special USB cable that’s supplied with the drive. It has two connectors fitted to one end, forming what is basically a "Y" configuration (see photo). One connector is wired for both power and data while the other connector has just the power supply connections. In use, the two connectors are plugged into adjacent USB ports, so that power for the drive is simultaneously sourced from both ports.

USB Cable

An external USB hard drive is usually powered by plugging two connectors at one end of a special USB cable into adjacent USB ports on the computer. This allows power to be sourced from both ports. According to the USB specification, USB ports are rated to supply up to 500mA at 5V DC, so two connected in parallel should be quite capable of powering a portable USB hard drive – at least in theory.

Complete Project

Unfortunately, in my case, it didn’t quite work out that way. Although the USB drive worked fine with several work computers, it was a "no-go" on my home machine. Instead, when it was plugged into the front-panel USB ports, the drive repeatedly emitted a distinctive chirping sound as it unsuccessfully tried to spin up. During this process, Windows XP did recognise that a device had been plugged in but that’s as far as it went – it couldn’t identify the device and certainly didn’t recognize the drive.

Plugging the drive into the rear-panel ports gave exactly the same result. The problem wasn’t just confined to this particular drive either. A newly-acquired Maxtor OneTouch4 Mini drive also failed to power up correctly on my home computer, despite working perfectly on several work computers.

Circuit diagram

The revised USB Power Injector is essentially a switch and a 5V regulator. The Vbus supply from USB socket CON1 turns on transistor Q1 which then turns on power Mosfet Q2. This then feeds a 6V DC regulated supply from an external plug pack to regulator REG1 which in turn supplies 5V to USB socket CON2.

Source: Silicon Chip 26 June 2008

USB AVR Programmer

noreply@blogger.com (Hendriono) — Sat, 16 Oct 2010 05:21:00 +0000

Introduction

Nowadays, USB is the most popular connection connection between PC and peripherals such as AVR programmers, printers, scanners etc. For that reason I had to modify my old serial AVR In-System-Programmer (ISP) to work with USB connection. You can say, "use a USB to Serial adaptor to connect your AVR ISP with your PC". Yes, that could be a solution but it would cost me more money than a singe FT232BM chip because I had to include an USB to RS232 adaptor and a power supply for my programmer. (almost €30).

So, the solution was to replace the two transistors, that were used to adapt the RS-232 voltage levels to TTL voltage levels, with a USB to RS-232 chip such as FT-232BM.

Initially, I used the John Samperi's firmware V3.2 but afterwards I found out the Klaus Leidinger's firmware that was a little bit faster. So, I chose the second one firmware but I had to modify the source code to work with 11.0592MHz crystal instead of 7.3724MHz that was initially designed because I couldn't find this crystal in the market .

This programmer worked perfect with AVRprog but then I found a software that could support much more AVR devices than the AVRprog could program. This software is AvrOspII V5.47.

The Circuit

Following the schematic diagram that I read in the FT232BM manual I made the connections between ATtiny2313 and FT232BM. The FT232BM requires a few and ordinary components to work. When you connect this circuit to your PC you will see the message " a new hardware was found" and then the factory name of FT232BM. IC1 is a serial EEPROM that used to store user's settings. So, you can rename this programmer to be appeared as "AVR In-System-Programmer" or "MyAVR programmer". Furthermore, you can add the firmware version of your circuit. Of cource, you can bypass this component because it's optional. I saw that the programmer works with or without this EEPROM. Anyway, FTDI suggests you to use this EEPROM. Led D1 flashes when data are transmitted or received by FT232BM. CN1 is a USB-B connector and CN2 is a 6-pin connector to your target AVR (it is connected to the AVR to be programmed). The S1 switch is used to supply your target circuit with +5V from the USB connector of your PC. In this case you won't need any additional power supply for your target circuit. Consider that a single USB port can supply up to 500mA current. You should not exceed this current limitation including the current that needs your AVR programmer too.

Programming the ATtiny2313

Burn the ATtiny2313 with avr910_2313_v38c.hex file. Do not forget to deselect the "Devide clock by 8 internaly" option and select the "Ext. Crystal Osc. 14CK + 65ms" option on fuses section of your AVR programming software.

Optional: Configure the USB programmer

As I said before, you can configure your programmer to be appeared with the name you want. In this case, my programmer is appeared as "AVR In-System-Programmer" when I plug it in to the USB port. Note that if you change any information on this screen you should change the same information in the "FTDIBUS.INF" and "FTDIPORT.INF" files. If you don't make any modification to the EEPROM and you have Windows XP SP2 or newer operating system, you won't need any driver. All the necessary drivers are included in your operating system.

The AvrOspII programming software

The programming software that was chosen is AvrOspII V5.47 (currently version) because it supports a lot of AVR devices and the author of this software Mike Henning is keep on writing new versions supporting new AVR devices. You can see if there is a new AvrOspII version available Here.

Credits

The AVR firmware was written by: Klaus Leidinger
The PCB was designed by: Dimitris Porlidas
The schematic diagram was drawn by: Dimitris Porlidas
The AvrOspII software was written by: Mike Henning
Small modifications in firmware and schematic diagram were made by: Vassilis Serasidis
Download Source: USB AVR Programmer
Readmore about USB AVR Programmer at here

36 Watt Audio Power Amplifier Using TDA1562Q

noreply@blogger.com (Hendriono) — Fri, 15 Oct 2010 17:10:00 +0000

It's based on a Philips class-H audio amplifier IC and can deliver 36W RMS OR 70W music power, all from a 13.8V supply. Our new Mighty Midget Amplifier can really pack a punch - around 36W RMS continuous into a 4-ohm load when using a 13.8V supply. However, it's the 70W of output power that it can deliver during dynamic (music) signal conditions that really make you sit up and take notice.

Figure 1. 36 Watt Audio Power Amplifier Using TDA1562Q

As can be seen from the photos and the circuit diagram, the Mighty Midget uses just a handful of parts. It's built on a PC board that measures just 104mm x 39mm but while its size may be modest, these's nothing at all modest about its power output. And the noise and distortion figures are pretty good too.

Circuit diagram:
Figure 2. 36 Watt Audio Power Amplifier Circuit Diagram

At the heart of the circuit is the TDA1562Q IC, described by Philips as a "monolithic integrated Bridge-Tied Load (BTL) class-H high-efficiency power amplifier". It comes in a 17-pin "DIL-bent-SIL" plastic package and is not only designed for use in car audio and portable PA work but for mains applications as well; eg, mini/midi audio components and TV sound.

Parts layout:
Figure 3. Parts Layout Of 36 Watt Audio Power Amplifier

PCB layout:
Figure 4. PCB Layout Of 36 Watt Audio Power Amplifier

Performance:

Output power:36W RMS into 4R
Music power:70W into 4R
Frequency response:1dB down at 28Hz and 55kHz
Input sensitivity:130mV RMS (for 36W into 4?)
Harmonic distortion:typically 0.2% (see graphs)
Signal-to-noise ratio:95dB unweighted (22Hz to 22kHz)

Source: Silicon Chip March 2002

Kicad - GPL PCB Suite

noreply@blogger.com (Hendriono) — Thu, 14 Oct 2010 18:24:00 +0000

Kicad is an open source (GPL) software for the creation of electronic schematic diagrams and printed circuit board artwork. Designed and written by Jean-Pierre Charras, a researcher at LIS (Laboratoire des Images et des Signaux) and a teacher in IUT de Saint Martin d'Hères.(France), in the field of electrical engineering and image processing.

Kicad is a set of four softwares and a project manager:

Eeschema :Schematic entry.
Pcbnew :Board editor.
Gerbview :GERBER viewer (photoplotter documents).
Cvpcb :footprint selector for components used in the circuit design.
Kicad: project manager.

With the project manager, Kicad, you can choose or create a project and launch Eeschema, Pcbnew, ....

This electronic workbench is free of charges and is open source (GPL). It is useful for everybody working in electronic design (schematic diagrams and Printed Board up to 16 layers).

This software (using WXWIDGETS) is MULTI-PLATFORM. It is running under LINUX and Windows (XP or 2000), for which updates are regularly provided.

Currently, the precompiled version of Linux has been tested using Mandrake 9.2 or 10.0 (works with 10.1).

Sometime the softwares are also been tested under other O.S., especially FreeBSD and Solaris.

With the schematic entry, you can:

Create simple or hierarchical sheets.
Test it with the Electrical Rules Check tool (ERC),
Create netlists for Pcbnew, or for Spice.

Eeschema manages a fast and direct access to component documentation.

The board editor Pcbnew works with 1 to 16 copper layers plus 12 technical layers (silk screen, solder mask ...) and creates all the necessary files for building printed boards ( GERBER files for photoplotters, drilling files and component location files).

You can plot board layers on PostScript laser printers (for prototypes).

Pcbnew can show a 3-D view of the printed board with its components (it uses OpenGL for this).

Price : Freeware/Open Source

Filesize : 112.008 KB

Website : Kicad

Download : FTP | HTTP | Library

3-30V 3A Adjustable Regulated DC Power Supply

noreply@blogger.com (Hendriono) — Thu, 14 Oct 2010 18:08:00 +0000

This power supply is meant as an auxiliary or as a permanent power supply for all common circuits based on a stabilized DC voltage between 3 and 30V provided that the consumption does not exceed 3A. Of course this power supply unit can also be used for other purposes. Be replacing the trimmer by a potentiometer, it may even be used as an adjustable power supply unit. A good quality heatsink must be used.

Picture of project:

Figure 1. 3 TO 30 Volt 3 Ampere DC Power Supply

Circuit diagram:

Figure 2. 3 TO 30 Volt 3 Ampere DC Power Supply Circuit Diagram

Parts list:

R1 = 8.2K
R2 = 2.2K
R3 = 680R
R4 = 1K
R5 = 82K
R6 = 0.18R/5W
C1 = 470p
C2 = 100nF-63V
C3 = 100nF-63V
C4 = 100uF-63V
C5 = 10KuF-60V
D1-D6 = 6.6A
Q1 = MJ3001 (Darligton)
IC1 = UA723D

Specifications:

Overload protected
Short-circuit stable
Output current: max. 3A
Output ripple voltage: 0.5mV
Output voltage: adjustable from 3 to 30V, stabilized
Input voltage: 9 to 30V AC (depending on the desired output voltage)

Assembling into a housing:

Depending on the transformer used, one may chose one of two housings
If a metal housing is used, it must be earthed for security purposes.
Make sure the cooling body does not touch the housing. This might cause a short circuit.
When mounting a toroidal transformer, it must be seen to that the fixation bolt does not touch the cover. This might cause the burning of the transformer
If the circuit is to be integrated into another housing, it must be provided with ventilation holes (one may make these holes oneself), necessary for the release of the heat developed.

Notes :

Connect a voltage meter to the points ‘GND’ and ‘+OUT’ and adjust ‘RV1’ until the desired output voltage is reached.
Apply some thermo-conducting pasta to the bottom side of the transistor and mount it on the heatsink.
If you need 3-8 volt then R2 will be 5.6K
If you need more than 8 volts then the R2 will be 2.2K
Suitable transformer 30vAC at 120VA

Source : 3-30V 3A Adjustable Regulated DC Power Supply

Digital Sensor Thermometer

noreply@blogger.com (Hendriono) — Fri, 10 Jul 2009 12:30:00 +0000

The TMP275 is a 0.5°C accurate, Two-Wire, serial output temperature sensor available in an MSOP-8 or an SO-8 package. The TMP275 is capable of reading temperatures with a resolution of 0.0625°C. The TMP275 is SMBus-compatible and allows up to eight devices on one bus. It is ideal for extended temperature measurement in a variety of communication, computer, consumer, environmental, industrial, and instrumentation applications. The TMP275 is specified for operation over a temperature range of −40°C to +125°C.

The easiest way to get the temperature out of the TMP275 seemed to be I2C. So I started by designing a board which has all the components needed: the sensor, an atmega8 brain, and some other components needed for the display and for powering the board. The display is a 4 digit 7 segment display from kingbright product code CA56-12GWA. As for the display part of the board, I used PNP transistors on the common anodes and resistors on the segments to limit the current draw on the atmega’s pins. The transistors are not current limited so the display will alaways light-up the same no matter how many segments are turned on.
For the supply part of the board, I choose to make it portable and power it from a 9V battery, so I needed to use a voltage regulator. The choice was the good old 7805 because it’s cheap and easy to find.

I2C is a pretty common protocol so various libraries can be found on the web. I chose Peter Fleury’s I2C library because it was very well documented. The only external components needed by the TMP275 are a bypass capacitor between VCC and GND and two pull-up resistors required on SDA and SCL lines.

All the I2C stuff is handled by the library, so I only had to write a couple of lines of code to get the temperature out of the sensor:

i2c_start_wait(sensor+I2C_WRITE); // set device address and write mode
i2c_write(0x0);   // write pointer register 00000000 to select temp register
i2c_rep_start(sensor+I2C_READ); //set device address and read mode
temp_high=i2c_readAck();  // Read high byte of temperature
temp_low=i2c_readNak();  // Read low byte of temperature

After reading the temperature from the sensor I had to display it on the 4 digit display. For that I had to write a display macro, which figures out the numbers and how to display them, basically I used software multiplexing. I even tested it on negative temperatures by placing the sensor in my fridge :) . The readout was correct because I checked with another thermometer.

These new type of digital sensors are great, because you don’t have to worry about analog to digital conversion, all the ADC is done inside the sensor. I mainly started working with this sensor because I want to incorporate a temperature reading function into a future project. Now that this part is done, is time to move onto the next one, ultrasonic range finder, which I’m guessing wont be as easy as the temperature reading.

I tried to comment every line of my code, but if you feel you don’t understand something, just post a comment and I’ll reply.

Download :

Source : YourTronic

Buzzer Water Level

noreply@blogger.com (Hendriono) — Thu, 02 Jul 2009 10:14:00 +0000

Buzzer Water Level

If you want to control the level of a water tank instead of connecting the V + and the collector of the transistor (Q2) at the buzzer is connected directly to a solenoid valve. And so every time you make contact electrodes by closing the valve.

Schematic
Original Source : Tektronico

Audio Generator Of Bells Ringing

noreply@blogger.com (Hendriono) — Tue, 30 Jun 2009 10:38:00 +0000

Overview
The circuit was designed similarly with door bell units as it generates an audio of bells ringing with dual tones.

Terminology

MC14106 – a hex Schmitt trigger constructed with MOS P-channel and N-channel enhancement mode devices in a single monolithic structure primarily used where low power dissipation and/or high noise immunity is desired due to its features of capability of driving two low-power TTL loads or one low-power Schottky TTL load, 3V to 18Vdc supply voltage range, and increased hysteresis voltage
BC337 – a small signal NPN Silicon AF medium power transistor used for general purpose switching and amplifying applications with features such as TO-18 manufactured package, suited for AF driver stages and low power output stages, and divided into three group types
Photoresistor – a resistor made up of high resistance semiconductor and whose resistance decreases with the increasing incident light intensity

Circuit Explanation
There are several applications by which this circuit can be used other than being a door bell. The common thing as compared with an ordinary door bell is that it produces a “ding” tone when the SPST push button switch P1 is pressed while a “dong” tone is created when P1 is released. The first tone is being generated by IC1D while the second tone is generated by IC1F. The shaping and fading of two tones are being controlled by Q2, Q5, and other related components while trying to replicate the natural sound of bells as close as possible.

The outputs are being mixed using resistors R7 & R13 and while being filtered by capacitor C5. In order to drive the loudspeaker, the outputs are being amplified by a simple Class A audio amplifier which is made up of Q3 & Q4. As the switch P1 is pressed, Q1 switches ON the amplifier then switches OFF after some seconds of releasing P1. The time delay is made possible by the parallel RC network from R2 & C1. A negligible current will be drawn at this stage when held in standby mode.

To create a “ding-dong” sound regardless of the release of P1, the circuit should be modified by removing D4 while the time delay between the first tone and second tone is arranged using C10 & R15. There is also a possibility of producing a single tone generator by doing more modifications on the circuit. The switch S1 can be excluded since the current being drawn at standby mode is 200 uA at 3 V, when in standby mode. The frequency of the tones is better set at approximately 2 KHz and 1650 Hz.

Application
One good application of this ringing bells generator is during Christmas where a soft bell sound can be heard at the switching ON and OFF of the chosen bulbs. This can only happen if a photoresistor is used in the place of P1 then placing the unit near the flashing lamps of the Christmas tree. A better way is to synchronize the circuit on the lights of the Christmas tree.

Schematic
Part List
Source:redcircuits.com/Page37.htm

The LYNX 150 Watt Bi-Polar Power Amplifier

noreply@blogger.com (Hendriono) — Tue, 30 Jun 2009 10:21:00 +0000

The LYNX v3.0 150 Watt Bi-Polar Power Amplifier - using Three Deep Darlington (TDD) Output Circuit.

The Design
Let me start by pointing out, that LYNX project from the beginning in 2002 had only one goal!
To create a rock-solid and powerful sonic Power Amplifier like those used in studio's.........
So if you are fond of the deceased mighty and "muscular" power amps from Phase Linear, SAE, GAS, Dynaco and similar ones, and if you like listening to live recorded LP's and CD's, you may be intrigued by this project as the result is very close to those.

Components
Components shown in the schematics are only suggestions. The circuit has shown good characteristics and produced good and clear sound when build with very low cost components. So with this circuit you have the possibility to either build a low cost dynamic Power Amplifier or a Studio Class Power Amplifier.
LYNX v3.0 Downloads
Schematic
PCB Component side
PCB Solder side
Quick Assembly Guide

Disclaimer
The LYNX circuit and PCB layout provided here is only for non-commercial diy build and use!
You are allowed to make your own PCBs for personal use, but please accept that in that case I do not provide any support! You are not allowed to make and sell copy PCBs!

Buy LYNX PCBs
You are able to purchase the new v3.01 LYNX PCBs at my webshop here:
www.audio-innovation.eu

Source : http://www.audio-circuit.dk/

How To Make PCBs

noreply@blogger.com (Hendriono) — Mon, 29 Jun 2009 16:46:00 +0000

First thing to do is make a schematic in EAGLE Layout Editor. Once you have done this you can then design the layout using Eagle too. Making schematic first helps because Eagle will show you clearly if you make any mistakes with the PCB.

Here is an example I will use, it is the prototype line stage used in my preamp:

Print it out onto some semi glossy photo paper. Be sure to select "solid black" in the eagle printing preferences and also un-select silk screen layers so that you only see pads and traces:

Then quickly take this paper, cut out your design and place it face down onto some blank PCB board. Then use an iron and press the design on to the board. Use A LOT of pressure and ensure all parts of the design make good contact with the blank PCB. Keep it pressed for at least 5 mins. I have found that having steam on/off makes no difference.

Then take your blank PCB with the design stuck on to it and soak it in soapy water for about 10 mins to loosen the paper:

Then CAREFULLY remove the paper. Be sure not to remove any of the black ink traces because these are what stops the acid in the etching process. I use a kind of rubbing motion to remove the paper. Keep it wet all the time so that it separates easily from the copper board.

Done and ready for etching:

Get some etchant and just follow the instructions for the dilution level. I just use a normal ceremic or glass bowel. Ghetto style:

Add boiling water from a jug:

And slowly swirl or rock the bowl around. The liquid must be always moving over the copper board to get it to etch properly.

Done!

Now give it a rinse in cold water and scrub the black ink off the PCB with a scratchy dish cleaner thing or steel wool.

Voila, you have a custom designed PCB:

Then all you need to do is drill out the holes and start mounting the components:

It will take maybe a couple of tries to get the hang of it but once you've got it you can produce perfect PCBs every time.

Tips for making PCBs:
www.expresspcb.com/ExpressPCBHtm/Tips.htm
Another guide like mine:
http://homepage.tinet.ie/~ei9gq/pcb.html
Some points to note:

You can't do it with Inkjet printers, the ink doesn't stick, don't bother trying.
OKI LED and regular laser printers work well.
I have only used matt photo paper and have always had perfect results, although glossy would probably work too. Otherwise you will have to experiment.
Once the design is stuck to the PCB put a blank piece of paper over the design and then rub and twist the iron while pressing the print on the PCB. This gives better coverage and makes sure it sticks on all parts of the PCB.

Here is some pics of another design I made (the soft-power circuit in my preamp):

This tutorial taken from No Spesific Topic