Kit - FM Wireless Mic 2 Transistor

This FK703 wireless microphone has two tuned stages for

extra stability and gain. Construction is simplified by the

adoption of etched resonant coils on the PCB. Its small outline

lends itself to use as a lapel microphone or security "bug". The

FK703 may be used with any FM radio receiver in public address

applications.

Technical data

- Power supply : 9VDC.

- Electric current consumption : 10mA. (max.)

- Transmitting frequency : 88 MHz

- IC board dimension : 1.64 in x 1.54 in.

How does it work

The microphone functions as receiver transmitting the sound

signal through C2 into leg B of TR1 which generates radio waves

and mixes them with the generated radio frequency. The mixed

signal will be sent through C5 toward leg B to boost the radio

frequency at leg C and transmit it to the antenna for

broadcasting. For easier assembly, an etched resonant coil is

adopted in lieu of a self made coil at legs C of TR1 and TR2.