Wireless-fm-microphone


Posted on May 7, 2012

Transistor Q1 acts as an amplifier for condenser microphone MIC1. The output of Q1 is applied to the base of transistor Q2 through a 4. 7 -I`F capacitor. C2 and 11 form an LC tank circuit. which is used to set the frequency at which the transmitter operates. Coil 11 is a variable inductor, centered a bit below 1~tH, that is used to adjust the modulating frequency of the circuit. Capacitors C1 and C2 are 4. 7 pF units. A lower value can be used to raise the circuit`s operating frequency. The microphone and Q1 provide a varying voltage at the base of Q2, with the output of Q2 applied to the LCtank circuit.


Wireless-fm-microphone
Click here to download the full size of the above Circuit.

That causes a modulating action in the tank circuit that, when applied to the antenna, a short piece of wire 6-to 8-inches long, will provide a good, clear FM signal somewhere in the range of 88 to 95 MHz with a range of about 100 feet.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Pulse Induction Metal Detector
Fiber-optic-receiver
Radio Commercial Zapper Circuit
3000w-stereo-power-amplifier-circuit.html
Door Lock Wiring
Voltmeter + Ammeter LCD panel
Negative Charge Pump with Ring Oscillator
Astable Multivibrator
micro stepper
bike battery charger schematics
Filament and Control Power Supplies
Wiring up to the AN2131
DC supply voltage the more limited indication circuit
Relay control circuit



Top