Simple Audio Amplifier


Simple Audio Amplifier circuit diagram

Here the simple and low cost audio amplifier schematic diagram. The circuit is ideal for a pocket radio or other hand held audio equipments.

The first part of the circuit here is a preamplifier consisting of transistor Q1(2N2222). The collector of the Q3 is coupled to the base of Q2 (2N2905A),which forms a complementary symmetry pair with Q3 (2N3053). The amplified signal is available at the junction of emitter of two transistors.


  • For Q1 you can try with any general purpose NPN transistors like BC107, BC148,etc.
  • For Q2 and Q3 you can try any complimentary power transistors. The result may vary slightly. No problem.
  • The can be also powered from a well regulated and filtered 9V DC power supply.


how can i adjust volume control to this circuit..

you can add the volume control by adding a 50K-100K potensiometer.

pin 1 connected to the output of module before amplifier (eq: radio, equalizer, preamp). pin 2 connected to the ground and pin connected to the input of audio amplifier.

how can i calculat the gain of this circuit..........??? how can i increase the gain of this circuit ???