Saturday, August 13, 2011

100Watt Bipolar Power Amplifier Circuit with BD139-BD140

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.

Audio Level Meter with 8 LEDs Indicator

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:
Audio Level Meter with 8 LEDs Indicator circuit diagram

Amplifier Power Indicator

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.

Amplifier Power Indicator circuit diagram

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)


  • 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

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

10 LEDs Audio VU Meter circuit

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.

Wednesday, August 10, 2011

500W 27Mhz RF Amplifier Circuit

500W 27Mhz RF Amplifier Circuit diagram

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

AM RF Amplifier Circuit for External Antenna

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

electronic circuit diagram

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:

5W / 150MHz RF Amplifier Circuit

5W / 150Mhz RF Amplifier Circuit diagram

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%.

Friday, August 5, 2011

Equalizer 3 band

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.

electronic circuit diagram

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

5-Band Equaliser Circuit

5-Band Equaliser Circuit diagram

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

4 Band Audio Graphic Equaliser Circuit

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

Wednesday, August 3, 2011

5W / 150MHz RF Amplifier Circuit

5W / 150Mhz RF Amplifier Circuit diagram

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%.

1W FM Booster based 2N4427

electronic diagram

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

Simple LM358 Mic Preamplifier

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

Tuesday, August 2, 2011

three up decision maker

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

Friday, July 29, 2011

50 Watt Amplifier

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.
This is the schematic of the 50 Watt Amp

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

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

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

  3. 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.

  4. Q1 and Q2 will require heatsinks.

  5. 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