The common base amplifier, on the other hand, reacts to an increased voltage on the emitter, ... it sure did a good job of making that little speaker into a decent microphone. Report comment. Reply.

Microphone amplifier experiment. I then wired up a small computer loudspeaker (8Ω) as a microphone, and tried it on both circuits. ... The impedance of the 8Ω loudspeaker working into the low input ...

Forward biased base-collector junctions only happen [in common emitter circuits] when the transistor is saturated, and the voltage across emitter-collector is about 0.2V Report comment Reply ...

I was playing around with some cheap CCTV microphone modules and managed to create a monophonic spy ear bug for common DVRs. They can be directly powered from the existing CCTV camera power supply ...