5 Wireless Microphone Circuit

The circuit is similar to FM bug but just to give emphasis, the use of this transmitter is for replacement of wireless microphone. The transmitter can be tuned to standard 90 to 108MHz FM band.
schematic diagram
Part List:
R1,R4, R7 - 5.6 kilo ohms 1/4W
R2 - 10 kilo ohms 1/4W
R3 - 4.7 kilo ohms 1/4W
R5, R8 - 2.7 kilo ohms 1/4W
R6 - 1.2 kilo ohms 1/4W
R9 - 200 ohms 1/4W
C1, C2 - 4.7uF electrolytic capacitor
C3, C6 - 100nF
C4 - 4.7pF
C5 - 5-60pF variable capacitor
Q1 - 2N2222, CS9013 or similar NPN transistor
Q2 - 2N2222, CS9013 or similar NPN transistor
L- 6-8 turns #22AWG magnetic wire diameter same as the pencil
Mic - electret microphone


  1. Wonderful article. I'm going through a few these issues.

  2. That is a grat circuit. were can i found a compatible receiver circuit?

  3. Any FM receiver will do with 88MHz to 108Mhz bands.
    example FM receiver in home stereo, car, cellphones, and others.

  4. This all part,s r not found in this market.They r saying this parts r too old.so..what 2 do?plzz..help me.

  5. Just replace its with any general purpose transistor if 2N2222 or 9013 are not available