- This circuit given here can be housed in the box containing the speaker to form a handy microphone amplifier.
- The device can be used by teachers,guides,lecturers etc for speaking in a crowdy or noisy environment.
- The circuit is designed base on the audio power amplifier IC TDA 7052.
- The IC can deliver a maximum power output of 1.2 W at a 6V supply.
- The audio signal from the microphone is pre amplified by the amplifier based on Q1 (BC 547) and give to the input of IC1 (pin 2).
- The POTR5 acts as a volume control.
- The capacitor C3 is used to bye pass the upper frequencies in order to avoid the Larsen’s effect(the microphone picking up speaker output to cause howls).
NOTES:
- Use a 8 Ohm speaker or two 4 Ohm speakers in series as load.
- Assemble the circuit on a good quality PCB or common board.
- A 6V SMF battery is my choice for powering the circuit.
- Switch S1 can be used as a ON/OFF switch.
