In stock: 100
FM Wireless microphone kit. Transmits mono FM from 88-108MHz. Batteries not included.
Brand: Tech America
Condition: new old stock
Additional Description: Theory of operation: the FM Mic Kit consists of two stages. The first stage uses a 3.3kohm resistor to bias the microphone. A 0.1 microfarad capacitor isolates the microphone from the base voltage of the transistor, allowing only AC signals to pass. The second stage consists of a BC547 transistor, a coil, a variable capacitor and a 470ohm resistor which form an oscillator circuit. The oscillated frequency can be adjusted by the variable cap from 88 to 108MHz