Dynamic Mic Amplifier (To Use Speaker as Microphone)

Tags

Dynamic Mic Amplifier (To Use Speaker as Microphone)

This is the circuit diagram of dynamic mic amplifier. This simple and easy built circuit can be used as a subtitute of an electret microphone. It will turn an ordinary mini speaker to become a pretty sensitive microphone.

Any NPN transistors can be applied for this circuit, for example: BC547. The circuit will operated from 3v to 9v DC supply. The amplifier configuration used in this dynamic mic amplifier is a common-base amplifier, it accepts the low impedance of the speaker to deliver a gain of more than 100 times.