FM Bug Transmitter Mint Box Circuit

Posted on Feb 5, 2014

Here is the circuit for the FM Bug. In total there are 18 core components that are needed for the fm transmitter to work properly. The far left side has the electret microphone and then things move electrically to the right until they hit the antenna. Don`t let this microphone fool you, it`s extremely sensitive albeit a bit clunky and big. You co

FM Bug Transmitter Mint Box Circuit
Click here to download the full size of the above Circuit.

uld shop around for a smaller microphone I`m sure but for this project, a standard electret microphone does the trick. The input is pulled high with a 22k resistor and passed to the amplifier circuit. The amplifier`s job in this circuit is to take the audio input and beef up the voltage/current so that when it gets transmitted it travels further. More amplification means more higher fm transmitting power and longer range. The last portion of the circuit with the 2nd BC547 is where the oscillator for the FM frequency is generated and mixed with the audio signal inorder to form the frequency modulation used for FM radio. Don`t worry, if all this is described a bit too quickly, the theory will be desribed more indepth in the next section.

Leave Comment

characters left:

New Circuits



Popular Circuits

80W power amplifier MJ3001 and MJ2501
DIY 6T9 Tube (Valve) Single-Ended Amplifier Kit
circuit How to find currents of all nodes using superposition theorem
usb audio multiplexer
low frequency sinewave
Audio VU Meter
AC Motor Speed Controller Circuit
Accurate Bass Tone Control
Single multi-lamp switch control circuit 2