Loudspeaker as a Microphone


Posted on Apr 6, 2012

This circuits allows you to use a cheap loudspeaker as a microphone. Sound waves reaching the speaker cone cause fluctuations in the voice coil. The voice coil moving in the speakers magnetic field will produce a small electrical signal. The circuit is designed to be used with an operating voltage between 6 and 12 volts dc. The first transistor operates in common base mode. This has the advantage of matching the low input impedance of the speaker to the common base stage, and secondly has a high voltage gain.


Loudspeaker as a Microphone
Click here to download the full size of the above Circuit.

The second stage is direct coupled and operates in emitter follower. Voltage gain is slightly less than unity, but output impedance is low, and will drive long cables. Speech quality is not as good compared to an ordinary or ECM microphone, but quite a




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

The 25-30kV DC Generator
Preregulator for power supply
Audio VU Meter using Arduino
24 Second Shot Clock Circuit
8051 flash programmer
am transmitter double side band
AC to DC 90 Watt Switching Power Adaptor PCB
BU8732AKV Codec Ic For Digital Mobile Phone
lm 3915 vu meter
PLL Stereo FM Transmitter
Rechargeable ago memory circuit
Digital circuit touch delay circuit 5
External protection signal generator by a circuit diagram TDA4866



Top