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Audio Amplifier Using TIP 147, 142

  1. Nov 14, 2015 #1
    << Obnoxious all caps post fixed by Moderators >>
    I have made an audio amplifier using an LM386 IC, but it does not amplify any sound from the microphone. Please help me to improve this using a Darlington pair or any other power transistor like the TIP147/142...
    Last edited by a moderator: Nov 15, 2015
  2. jcsd
  3. Nov 14, 2015 #2


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    Please don't use uppercase lettering ... its considered shouting when typing online

    OK you haven't given us enough info to help you
    how about circuit diagram if what you have built and maybe a photo or 2 of your construction so that the wiring can be checked for errors

  4. Nov 14, 2015 #3
    Also, please add any information you have about your microphone.
  5. Nov 14, 2015 #4
    I have cascaded these two , means first i install the Common colletor because of high input impedence and then i apply its output from emitter to LM386 ... but theere is no sound which i applied on common collector base. which type of microphone should i use for this.. plz guide me.

    Attached Files:

  6. Nov 15, 2015 #5


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    Well, the common collector stage you have shown is just a textbook drawing. What does your real circuit look like?
  7. Nov 15, 2015 #6

    output speaker specs is: 4Ohm, 3 Watt

    Attached Files:

  8. Nov 15, 2015 #7


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    Staff: Mentor

    Your common-collector stage needs fixing! You'll almost certainly need a capacitor to couple the signal from the mic to the base, and this capacitor needs to go directly to the base (you are showing the mic wrongly connected directly to the power rail, Vcc).
  9. Nov 16, 2015 #8
    you please draw the picture on peper and send me here? as it does not work till now.
  10. Nov 16, 2015 #9


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    Here is a schematic for a "common collector" stage.
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