Rabu, 05 Januari 2011

Component Series Wireless Microphone


Component Series Wireless Microphone

R1 = 10K (brown-black-orange)
R2, R3 = 100K (brown-black-yellow)
R4 = 470 ohms (yellow-violet-brown)
C1, C3 = 4.7pF (4p7), ceramic
C2, C4 = 4.7uF-16V, electrolytic
C5 = 0.001uF (1NF), ceramic
C6 = 470pf ceramic
Q1, Q2 = 2N2222, NPN transistor
L1 = 1uH, variable inductor
Mic = Electret mike, 2 wires
Couple Notes:
Q1 amplifies the input signal via C4 from the electret microphone.
Q2 acts as an oscillator and the signal coming off C2 is fed onto the base of Q2.
L1/C1 is a so called 'tank' circuit and operates in the 88-105MHz band on your regular AM / FM radio dial.
L1 is a 1uH variable inductor coil to be Able to tune it a little bit, and the range of 1uH is approximate.
The antenna cans be as simple as a 8 "(21cm) piece of wire of any kind.

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