Signal tracer circuit.


A high gain amplifier circuit that can be operated from a battery pack of 6 or 9 volt battery pack is shown here.The IC1 uA 741 is wired as a high gain non-inverting amplifier and its output is amplified by a pair of complementary transistors (Q1 & Q2) to drive the speaker.The negative feedback from the common emitter junction of the two transistor stabilizes the gain of the circuit.The resulting audio output is sufficient to serve as a signal tracer.

Circuit diagram with Parts list.



  • Assemble the circuit on a  good quality PCB or  common board .
  • The POT R6 can be used as a volume controller.
  • The circuit can be powered from a 6 or 9V DC battery pack.
  • The IC1 must be mounted an an IC base.
  • All capacitors must be rated at least 15V.
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10 thoughts on “Signal tracer circuit.

  1. seetharaman

    Hi George
    3 ohms is too low an impedance for this amp. try with 8 ohms it will be ok. or with 2nos 8 ohms speaker in series it will be still better. ensure output transistors are the recommended germanium matched pair only(this pair requires very low standing current to avoid crossover distortion).

  2. george

    I built the circuit from the picture, and there is one issue to deal with: when I put 60 Ohm headphones, everything sounds good. But when I put 3 Ohm loudspeaker, the distortion is heard from it. I know this is not the right place to ask such question, but what should I do to solve this issue?


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