Here is a simple head phone amplifier circuit that can be used to drive your head phone if your music player doesn’t have enough power to drive your head phones.The circuit is straight forward and uses only three transistors.
The transistor Q1 (BC 239) and associated components forms a pre amplifier.The transistor pairs Q2 & Q3 (BC 337 & BC 327) forms the driver circuit for the speaker. Power amplification is attained at this stage.The emitter voltage of Q1 is fed back to base of Q1 via R3 in order to improve performance and reduce distortion.
Circuit Diagram with Parts List.
- The circuit can be powered from a 3V battery.
- The switch S1 can be used as an ON/OFF switch.
- Assemble the circuit on a good quality PCB or common board.
- All capacitors must be rated 10 V.