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12 Watt Transistor Amplifier Circuit

admin March 19, 2008 19 Comments

 About the circuit.

This is a low cost amplifier circuit using 4 transistors and one op amp. The op amp uA 741 produces the required gain and the transistors wired in complementary Darlington configuration produces the drive for the speaker.

The input for the Darlington pairs are derived from the power supply as a voltage drop across R2 and R3.The voltage drop across these resistors will be proportional to the input signal because the supply current to the op amp varies according to the input signal .The negative feedback from the junction of Q4 and Q2 stabilizes the amplifier. This circuit will produce a decent 12W out put power on a 4 Ohm speaker .

Circuit diagram and parts list.

12-w-transistor-amplifier_circuit_al.JPG

Tips. 

  1. Use a  +12 , -12 , 1A  dual power supply for powering the circuit.The power supply must be well regulated and filtered to reduce the noise.
  2.  Wire the board on a good quality PCB or common board.
  3. Do not give more than +15 , -15   volts to the circuit.
Comments
  • September 4, 2008

    nqwbapioe niga vtcfhpr yqprvtd jvhe nvswomd pcoyejuqf

  • himanshu
    November 20, 2008

    give some more information about this circuit

  • Oyewole Bukola A
    February 13, 2009

    pls, i need construction of slave engine amplifier with circuit diagram

  • Osama
    May 25, 2009

    I cant find Q1 AC108 anywhere on the web too….where is its data sheet, neither it is present at Electronic WorkBench….plz sombody help me

  • saqlain
    July 27, 2009

    very god circiut.i m working this circuit

  • August 19, 2009

    please i would love to have the principle of operation of the circuit of the 12 watt amplifier circuit.

  • steve
    November 13, 2009

    ii like the circuit

  • jalal
    January 11, 2010

    hello
    how are you
    i live in iran -tank you for this website.
    please give me a circut shok,
    see you byby

  • Ronald
    January 12, 2010

    Hello
    I am interested to build this amp.
    Please send me copy of PCB layout

    Thank you
    Ronald

  • Fish
    May 6, 2010

    fish nana hip HIP

  • Fish
    May 6, 2010

    i need a 20 watt audio amplifier with a transistor output. pls tnx FISH..

  • May 17, 2010

    hi am Ismail and am requsting you to send me a diagram of an ampwhich will work with my,pioneer impp 450watts speaker without hamming.thank you

  • September 8, 2010

    12 Watt Transistor Amplifier Circuit…

    This is a low cost amplifier circuit using 4 transistors and one op amp. The op amp uA 741 produces the required gain and the transistors wired in complementary Darlington configuration produces the drive for the speaker…….

  • September 8, 2010

    12 Watt Transistor Amplifier Circuit…

    This is a low cost amplifier circuit using 4 transistors and one op amp. The op amp uA 741 produces the required gain and the transistors wired in complementary Darlington configuration produces the drive for the speaker………

  • September 22, 2010

    i cant determine the electrical meaning.

  • September 22, 2010

    if R1 10k, how many watts of this?
    what is the name of the each resistors?
    please help me !

  • December 28, 2010

    Don’t take the 300mA I mentioned too serious. It’s a good bias, but I just added a zero to the resistance value as a quick estimation, and ended up with that bias. So use whatever bias you please.

  • February 11, 2011

    hi my name is uche from nigeia pl,s cant you send me jrc4558orne555. 2000W POWER AMP

  • Tshepo
    February 26, 2011

    hi,i really love doing elecronics, but i would be really excited if you can send me a mail about new curcuit drawings and explanation on hoe they work. im intrested in amplifires, resistors, transistors, dioeds etc.

    thank you

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