circuits

100Watt Bipolar Power Amplifier Circuit with BD139-BD140

2011-08-13T06:27:00.000-07:00

This is a basic 100 watt power amplifier designed to be (relatively) easy to build at a reasonable price. It has a better performance (read: musical quality) than the standard STK module amps that are used in almost every mass market stereo receiver manufactured today. When I originally built this thing, it was because I needed a 100 WPC amp and do not want any money. So I designed around parts I had in the store.

The design is actually a standard format, and I’m sure there are commercial entities that are similar. To my knowlwdge, it is not an exact copy of a commercial entity, nor am I aware of any patents on topology. For experienced builders: I am aware that many improvements and adjustments can be made, but the idea was to keep it simple and must do-able by anyone who is a circuit, and has not the patience to do a sloppy job.

If friend want Bipolar Transistor power amplifier circuit. , In model HIFI OCL 100W RMS. I think this track should be an interesting choice, this circuit is the use of the key transistor BD317 and BD318 unless transistor number BD139, BD140, BC556 too easy then try to buy when the 35V power source with only then build is not difficult for other details as the result of a few See Circuit. Input stage is a BC556 transistor, which most of the open loop gain, and on the serene DC voltage stabilizes. This feeds a level shift stage where the voltage swing to (-) track references. The Transconductance stage is a Darlington, improve frerqency high linearity. The BD317, 318 on a rather large collector-base capacity is dependent on voltage. The BD319 presents this low-z and has a C (ob) of only a few of PF, which is effectively swamped by the pole-splitting 220pF cap. The scene is supplied by BC546 active load (current), which is approximately 20 mA. The current, until the BC556 is limited to about 70 mA in the worst cases.

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Audio Level Meter with 8 LEDs Indicator

2011-08-13T06:19:00.001-07:00

This audio level meter required 2 pieces of LM324 for each channel. Every single LM324 contain 4 op-amps, then you need 2 pieces of LM324 to cover 8 LEDs. And need 4 piece of LM324 for 16 LEDs (for stereo channel)
Here the schematic:

Amplifier Power Indicator

2011-08-13T06:18:00.001-07:00

This is one of many audio level indicator circuit. The different is that this circuit should be connected tho the output of amplifier while the other indicators connected before amplifier module. This circuit will show the real audio output by LED indicator level.

R1_____________220R  1/2W Resistor
R2,R5,R6,R8____100R  1/4W Resistors
R10,R12,R14____100R  1/4W Resistors
R3_____________220R  1/4W Resistor
R4,R7__________330R  1/2W Resistors
R9_____________560R  1/2W Resistor
R11____________820R  1/2W Resistor
R13______________1K2 1/2W Resistor

D1___________1N4004  400V 1A Diode
D2,D4,D6__BZX79C2V7  2.7V 500mW Zener Diodes
D3,D5,D7,D8,D9,D10   Red LEDs (Any dimension and shape) (See Notes)

Notes:

The output power indicated by each LED must be doubled when 4 Ohms loads are driven.
The circuit can be adapted to suit less powerful amplifiers by reducing the number of LEDs and related voltage dividers.
LEDs of any dimension can be used, but rectangular shaped devices will be more suitable to be compacted in bars or columns.
For a stereo amplifier, two identical circuits are required.

10 LEDs Audio VU Meter circuit with LM3915

2011-08-13T06:17:00.000-07:00

This is very nice VU meter circuit for your own audio system project.

Build based IC LM3915, this circuit will indicate the power audio level of your audio system. This circuit is very simple, inexpensive and easy to build.

Visit this page for complete explanation. Follow the instruction and use the proper power supply for this circuit.

500W 27Mhz RF Amplifier Circuit

2011-08-10T06:36:00.000-07:00

Parts List:
C1,C3 = 75-380 pF mica trimmer, ARCO 465
C4-C8 = .01 uF 1 kV disc ceramic
C9,C10 = .1 uF 500V disc ceramic
L1 = 6 uH. 25t #24 ga.enam. 0.5" dia.
L2 = 210 nH. 4t #8 ga. .75" id, 1" long
L4 = 2t #20 PTFE on .5" ferrite bead m=850
Q1 = APT ARF448A
R1 = 25W 5W non-inductive
T1 = Pri: 4t #20 PTFE, Sec: 1t brass tube on 2 hole balun bead. Fair-Rite #2843010302 m=850

High voltage MOSFETs are now available that combine the best practices from the RF world with the economy of the switchmode devices and packaging. They are available in mirror image pairs and the heat spreader of the plastic TO-247 package is connected to the source.

Download the aplication note for this circuit 500W 27Mhz RF Amplifier HERE

AM RF Amplifier Circuit for External Antenna

2011-08-10T06:35:00.001-07:00

This is an AM RF Amplifier Circuit for External Antenna which built using RCA 40468A FET. The detailed explanation and recomendation about this circuit, go tothis page.

60W Linear RF Amplifier Circuit

2011-08-10T06:34:00.000-07:00

The 60 Watt linear rf amplifier is easy all solid state circuit applying power mosfet IRF840. The IRF series of power transistors are provided in a number of voltage and power ratings. A single IRF840 can carry out maximum power output of 125 watts. Because these transistors are applied in inverters and smps, they're simply presented for about Rs: 20/-.

The IRF linear amplifier could be connected to the out put of well-known VWN-QRP to obtain an output of 60 Watts. The circuit draws 700 ma at 60 Volt Vcc. Great heat sink is actually a ought to for the power transistor.

Alignment of the circuit is quite effortless. Connect a dummy load to the out put of the circuit. It is possible to use some modest bulb like 24V 6Watts as the dummy load. I've even utilized 230V 60Watts bulb as dummy load with my IRF840 power amplifier working at 120Volts. Adjust the 10K preset to obtain about 100 ma Drain current. I applied gate voltage of 0.8V with my linear amplifier. A heigh gate voltage can make the power transistor get distroyed by self oscillation. So gate voltage ought to be below 2V and fixing at 1V is going to be secure.

Bifalar transformaer T1 is wound with 8 turns 26SWG on 1.4 x 1 balun core. The coil on the drain of IRF is 3 turns 20 SWG wound on 4 number of T13.9 torroids (two torroids are stacked to form a balun core). The RFC at the Vcc line is 20 Turns 20 SWG wound on T20 torroid.

60W Linear RF Amplifier circuit source:
http://www.flashwebhost.com/circuit/60_watts_rf_amplifier.php

5W / 150MHz RF Amplifier Circuit

2011-08-10T06:32:00.000-07:00

This is a 5W -150MHz RF amplifier circuit. It applies the MRF123 TMOSFET. The MRF123 is a very high gain FET which potentially unstable at both VHF and UHF frequencies, so the 68 Ohm input loading resistor has been used to enhance the stability. This RF amplifier has a gain of 14 dB and a drain effeciency of 55%.

Equalizer 3 band

2011-08-05T00:36:00.000-07:00

This is mono 3 band equalizer circuit. The circuit is simple, cheap and easy to built. You should make two circuits for your stereo audio system.

Supply voltage may be anything from 6 to 30 Volts. Maximum boost 20dB is only realized with maximum supply voltage.

5-Band Equaliser Circuit

2011-08-05T00:34:00.000-07:00

Above circuit is a 5-Band graphic equaliser circuit from Electronic For You Magazine, published May 2007. This equaliser uses low-cost op-amps NE5532 or LM833. Those ICs are good-quality op-amps powered by a single voltage supply are readily available in the market.

This 5-Band equaliser circuit is powered by a 12V DC regulated power supply. A well-regulated power supply using 7812 is recommended.

Download 5-Band Equaliser Circuit document from Electronic For You Magazine:
» Download Link

4 Band Audio Graphic Equaliser Circuit

2011-08-05T00:33:00.000-07:00

This is the circuit of 4 band audio graphic equaliser. The equalizer will cut and boost the four range of audio frequency, that are:

Low frequency: Freq. 35-680Hz
Medium frequency: Freq. 150-3kHz
Medium/semi high frequency: Freq. 450-8.5kHz
High audio frequency: Freq. 750-15kHz

Circuit note: Use regulated power supply, metalfilm resistor, MKM nonpolar capacitor and tantalum bipolar capacitor for best audio quality result.

This circuit is available in PDFdocument. Download 4 Band Equalizer circuitfrom the following link:
Download Link

5W / 150MHz RF Amplifier Circuit

2011-08-03T02:57:00.000-07:00

1W FM Booster based 2N4427

2011-08-03T02:54:00.000-07:00

This is the circuit diagram of linear FM Booster / RF amplifier based 2N4427 Philips transistor. The RF Amplifier is for boosting small fm transmitters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More voltage can boost the distance but the transistors will be burned much earlier than usual.! In any case do not exceed the 15Volts. The Amp offers 15 dB in the area of 80Mhz to 110 Mhz. L4, L5, and L6 are 5mm diameter air coils, 8 turns, with wire 1mm wire diameter. This is an easy project, but will give you great results.

Simple LM358 Mic Preamplifier

2011-08-03T02:51:00.000-07:00

This is a simple LM358 microphone preamplifier schematic diagram. The pre-amp circuit is very easy to build and.. it's a low cost project... The variable resistor R5 is to adjust the LM358 op-amp gain. The LM358 has dual op-amp circuit modules, you may use a single LM358 to build two channels mic preamplifier.

Parts List:
R1, R3, R4 = 10K
R2 = 1K
R5 = 100K-1M Potensiometer
C1 = 0.1uF
C2 = 4.7uF/16V
IC1 = LM358 dual op-amp single power supply
Mic = Electret Microphone

three up decision maker

2011-08-02T08:49:00.000-07:00

PCB Layout

This electronic device will help you make important decisions (or not). While it is deciding the solution to your problem it will convince you how difficult it really is by a painful growling noise - or maybe this is normal when you have to think!

Once the push button is pressed, the circuit uses a 555 Timer in a astable (free running multivibrator) fashion. The mathematics indicate that we should be getting a square wave signal at a frequency of around 124 Hz ( cycles per second) see 555 Worksheet. This signal is fed into the4017 Decade Counter which counts 0 - 1 -2 - RESET. Where RESET is an instantaneous process that sets the counter to 0. For all purposes, the count is 0 - 1 - 2 - 0 - 1 - 2 .............. This counting sequence is produced at pins 2, 3 and 4 of the 4017 . We have assigned pin 2 as NO, pin 3 as MAYBE and pin 4 as YES. The output from the 4017 is passed through 390 ohm resistors to limit the current (protect the 4017) before passing through the coloured LED's to 0V. The push button also supplies current to the buzzer making the noise while it decides.

When the push button is released the 555 stops the signal and the 4017 displays the current count YES, NO or MAYBE.

To construct the project

1. Check the PC Board for damage or breaks in the tracks. A CdS Circuit Tester is ideal, or use a continuity tester mode on a multimeter. Repair any damaged tracks.
2. Push the IC sockets into their holes. One has 8 pins, the other 16. The pads on the board will match the legs. Note that there is a notch in one end of the sockets. On the layout sheet there is an instruction about the locating DOT of each IC. If you turn the IC sockets so the notch is where the locating dot is to go, then you will be saved a bit of thinking later when you are ready to push the ICs. into place. Push the sockets right down to the board. It is strongly recommended that you solder the sockets in place right away. See Soldering Technique . Any spreading of solder across to the fine tracks between the pads will prevent the project from working.
3. Identify the resistors by their colour bands See Resistors , and check with a multimeter. Bend the legs to match their holes and mount them to the board. Spread the legs on the other side to hold them in place. They may be soldered if convenient.
4. The polyester capacitor (greencap) can be inserted. They are not polarised so can go any way round.

5. The electrolytic capacitor is polarised. The negative stripe on the capacitor shows the negative leg.

6. The LED's are polarised. Insert them in the correct polarity and colour placement. The A leg is longer.
7. The Piezo transducer has Red (+ ve) and Black (-ve) leads. The board is marked for correct connections. The holes in the board at these points are larger to take the pins in the Kit. This makes termination of the wires much easier.
8. Remove the ICs from their anti-stat cases and identify them - 8 & 16 legs. You will find that the legs are spread too wide to fit easily into their sockets, so hold one set of legs sideways on a flat surface and press down to bend them inwards a little. Follow with the other side. Offer the IC to its socket and check that the legs have been bent in enough to slide into the socket. Look for the locating DOT and turn the IC to match the sheet. Push it firmly into place. Repeat the process for the other IC.

9. Offer the holder into the two holes and push home. Note the battery holder is inserted from the track side of the PCB. Apply the soldering iron to the legs in turn until you have pushed the holder down close to the board. Next, fuse the solder to both pads and legs to form a good contact.

10. Attach the switches in their respective positions. Insert a bettery and test the project.

Generally the unit will work right away. If it refuses then you must check locations, values, and polarity of all components against the layout sheet.
If these check out then remove the battery holder and inspect all soldered joints. Re-solder any that look suspicious, in fact you could touch each joint with a hot iron to eliminate any soldering problems.
You might check the track again to locate any fine breaks,

Contact CdS electronics

50 Watt Amplifier

2011-07-29T18:59:00.000-07:00

This is a handy, easy to build general purpose 50 watt amp. The amp has an input for a radio, TV, stereo or other line level device. It also has a phono input for a record player, guitar, microphone or other un-amplified source. With the addition of a low pass filter at the input, it makes a great amp for a small subwoofer.

Parts

R1(1)200 Ohm 1/4 W Resistor

R2(1)200K 1/4 W Resistor

R3(1)30K 1/4 W Resistor

R5(1)1K 1/4 W Resistor

R6(1)5K 1/4 W Resistor

R7,R10(2)1 Meg (5%) 1/2 W Resistor

R8,R9(2)0.4 Ohm 5 W Resistor

R11(1)10K Pot

R12,R13(2)51K 1/4 W Resistor

R14(1)47K 1/4 W Resistor

C1(1)100uF 35V Electrolytic Capacitor

C2(1)0.011uF Capacitor

C3(1)3750pF Capacitor

C4,C6(2)1000pF Capacitor

C5,C7,C8(3)0.001uF Capacitor

C9(1)50pF Capacitor

C10(1)0.3uF Capacitor

C11,C12(2)10,000uF 50V Electrolytic Capacitor

U1,U2(2)741 Op Amp

U3(1)ICL8063 Audio Amp Transister Driver thingy

Q1(1)2N3055 NPN Power Transistor

Q2(1)2N3791 PNP Power Transistor

BR1(1)250 V 6 Amp Bridge Rectifier

T1(1)50V Center Tapped 5 Amp Transformer

S1(1)SPST 3 Amp Switch

S2(1)DPDT Switch

F1(1)2 Amp Fuse

SPKR1(1)8 Ohm 50W Speaker

MISC(1)Case, Knobs, Line Cord, Binding Posts Or Phono Plugs (For Input And Output), Heatsinks For Q1 And Q2

I know I skipped R4. That is not a problem :-)

Distortion is less than 0.1% up to 100HZ and increases to about 1% at 20kHz.

I haven't been able to find anyone who sells a suitable T1. You can always use two 24V 5A units in series. If you are building two amps (for stereo), then I would suggest using an old microwave transformer and rewinding it. Follow the instructions in the 12V To 120V Inverter, execpt wind 26 turns, twist a loop (center tap) and wind 26 more turns. That should work out to around 50 volts. You may need to add or remove turns depending on your transformer.

Q1 and Q2 will require heatsinks.

You may have trouble finding U3 because it is discontinued. Please don't email me about sources...I can't find it either. See if any of the sources in Where To Get Parts has it. A possible source was sent in by JBWilliams

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easy and reliable amp

2011-07-19T18:30:00.000-07:00

Headphone monitor amp

2011-07-19T18:21:00.000-07:00

This simple amplifier is ideal for adding a headphone jack to equipment that lacks this feature. The Headphone Buffer circuit board is small enough (1.2" X 1.4") to squeeze into even the smallest spaces and power requirements are so low that existing supplies in retrofitted gear can be used. It's a useful addition to many PAiA products such as the Submixer or Submix-Master. Adding a headphone output turns a Stack-In-a-Box it into an incredible practice amp.

The key component is the 5532 Dual OpAmp. While ordinarily this part is chosen for it's low noise characteristics, it is also capable of delivering nearly 350mW of output power per side, more than enough to drive headphones. The circuit can operate from bipolar voltages from +/-5V to +/-18V and it is not absolutely necessary that the + and - supply voltages be the same magnitude. The superior supply voltage rejection of the IC allows operation with unregulated supplies.

In the typical mono application such as adding headphones to a FatMan or Theremax, the Left and Right inputs of the amp are both connected to the Volume control supplied with the kit. For stereo applications a dual ganged pot should be used and this modification is covered in the instructions.

The Headphone Buffer amp kit includes circuit board, all electronic components, 1/4" Stereo Jack, Volume control w/knob, wire and assembly instructions.

Two Transistors Audio Amplifier

2011-07-19T18:14:00.000-07:00

ping pong circuit schematic

2011-07-15T09:01:00.001-07:00

Rain Detector

2011-07-13T06:43:00.000-07:00

This circuit uses a sensor made of a small piece of etched PC board and a simple SCR circuit to detect rain and sound a buzzer. The SCR could also be used to activate a relay, turn on a lamp, or send a signal to a security system.

Parts

R1(1)1K 1/4 W Resistor
R2(1)680 Ohm 1/4 W Resistor
D1(1)1N4001 Silicon Diode
BZ1(1)12V Buzzer
S1(1)SPST Switch
SCR1(1)C106B1 SCR 106CY
SENSOR(1)See Notes
MISC(1)Board, Wire, Case, PC Board (For Sensor)

Notes

The sensor is a small piece of PC board etched to the pattern showen in the schematic. The traces should be very close to each other, but never touching. A large spiral pattern would also work.

Make sure to use a loud buzzer.

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Mini-MosFet Audio Amplifier

2011-07-11T07:18:00.000-07:00

Notes
This project was a sort of challenge: designing an audio amplifier capable of delivering a decent output power with a minimum parts count, without sacrificing quality.
The Power Amplifier section employs only three transistors and a handful of resistors and capacitors in a shunt feedback configuration but can deliver more than 18W into 8 Ohm with <0.08% THD @ 1KHz at the onset of clipping (0.04% @ 1W - 1KHz and 0.02% @ 1W - 10KHz) and up to 30W into a 4 Ohm load.
To obtain such a performance and to ensure overall stability of this very simple circuitry, a suitable regulated dc power supply is mandatory. This is not a snag because it also helps in keeping noise and hum of the preamp to very low levels and guarantees a predictable output power into different load impedances. Finally, as the amplifier requires only a single rail supply, a very good dc voltage regulator capable of supplying more than 2 Amps @ 40V can be implemented with a few parts also.

Interior light extender

2011-07-09T18:36:00.000-07:00

1. Mount components to the PCB from the PLAIN SIDE. Polarity must be observed for DI, (Power Diode) and for CI (Electrolytic Capacitor).
(i) DI - Band on Diode is at K (-ve) end
(ii) CI - Arrow on Body of Capacitor points down the negative leg.
Push the component legs through, nip off 1-2mm clear of the bus-bars and bend leg's in opposite directions. This will hold the components in place.
2. TI (BC558) should be mounted with the flat section in the direction shown.
3. T2 can be mounted as follows:
(1)  Turn the end of a piece of link wire to a ring and solder together. This ring is attached to a hole in the transistor body by a 1/2 x 1/8" Metal thread screw. The link wire is cut and soldered at B1 - B6.
(2) The legs on the transistor are too large to fit into the holes in the Veroboard so solder short lengths of link wire to the transistor legs and solder these to the PCB.
4. Solder electrical wire from Kit to 12V + and 12V - positions.
5. To wire to automobile circuit, the following procedure is recommended.
(a) Locate the wire from the Interior Bulb to the switch activiated by the car door.
(b) Determine that the car has a Positive Earth or Negative Earth Wiring system by checking the battery. (Most cars use negative earth).
(c) For Negative Earth System join the 12V +ve wire from your project to the wire from bulb to switch using the wire-tap from the Kit. For Positive Earth system join 12V -ve wire instead.

(d) Ensure that the cover on the wire-tap is folded into place so that no bare metal is exposed.
(e) Join the 12V -ve wire from your project to a suitable earth point on the car body. (For Positive Earth system read 12V +ve).
NOTE: Do not cut existing wiring to the interior light just join the project in parallel with the switch.
(f) Test the unit for correct function.
TROUBLE SHOOTING
(i)  Check for dry joints, joints not soldered at all, or solder bridging PCB tracks.
(ii)  Check polarity of D1 (Diode) C1 (Electrolytic Capacitor) T1 BC558 PNP Transistor and T2 2N3055 NPN Transistor must be mounted as shown in diagram.

(iii) Check locations of all components.

Technology Notes

All modern cars are fitted with door-switch operated courtesy lights. Useful devices, but not quite as useful as they might be because they are so arranged that the light is extinguished as soon as you close the door - just when you need light to find the ignition switch. do up your seat belt etc. How much better if the internal light stayed on for a few seconds after the door is closed. This little project does just that. It provides a four-second delay (approx) after which the interior light slowly dims - being finally extinguished after 10 or 12 seconds. The unit is very simple to construct and once tested and properly insulated it may be wired across one of the car door switches. In operation, after a short delay the lights will gradually dim until they are completely extinguished. There is no battery drain in the off-state as the unit only operates during the delay period after the door is closed.

Most car door switches am simply simglec-pole switches. with one side earthed. When the door is opened the switch earths the other line thus completing the Light circuit.

In a car whem the negative terminal of the battery is connected to the chassis the nerative wire of the unit (emitter of Q2) is connected to the chassis and the positive wire (case of 2N3055) Is connected to the wire going to the switch. In. a car having a positive earth system this connection sequence is reversed.

When the switch closwe (door open) C1 is discharged via DI to zero rolts and when the switch opens, C1 charges up via R1 and R2. Transistors QI and Q2 are connected as an emitter follower (Q2 just buffers Q1) therefore the yoltage across Q2 increases slowly as C1 charges. Hence Q2 acts Like a low resistance in pars1lel with the switch - keeping the lights on.

The value of C1 is chosen such that a useful light level is obtained for about four seconds, thereafter the light decreases until in about 10 seconds it is out completely. With different transistor gains and with variation to current drain due to a particular type of car the timing may be simply adjusted by selecting C1.

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15W mono car amplifier using TA7227P

2011-07-09T18:29:00.000-07:00

source

Build a good Audio Buffer Amplifier

2011-07-09T07:17:00.000-07:00

General Description:
This circuit will amplify voice audio in the range of 50 to 10,000 cycles with little distortion, and have the ability to drive a low impedance load to 16 ohms. The circuit will run from 6 to 15 vdc and give about 20 dB of gain.
Concept:
To build an inexpensive audio amplifier with little parts count that is very reliable and easy to build and implement. Parts are available from Radio Shack.
Construction:
Build the circuit on a breadboard and use a socket so when the lightning hits, well you know......
If the audio input is biased above ground (audio floats on a voltage) a coupling cap will need installed in the "Audio In" lead to the pot. The pot can be any value from 5 K to 100 K. The 100 pF helps eliminate RF bombardment, making it suitable for higher RF environments. Don't forget the 100 uF cap or the circuit will oscillate.
Many op-amp circuits don't drive low impedance loads well, this circuit will handle a load impedance to about 16 ohms but doesn't need to be loaded down to that impedance. The output cap is a 10 uF non polarized electrolytic for impedance's to 600 ohms. The output capacitance should be raised to 100 uF for impedance's to 100 ohms and to 1000 uf for impedance's below 100 ohms (speaker.)
Operating bandwidth is from 50 cycles to 10 kc. Over 10 kc and the unit suffers from poor slew rate, causing distortion, but for NBFM this bandwidth is acceptable. Actually, for this purpose slew rate limitations work to our advantage as it helps make the amplifier less RF susceptible. Increased audio amplification can also be had with the addition of a feedback loop. Consult the RS parts substitution manual for examples.

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