Simple long-distance wireless microphone circuit

Published:2012/8/27 21:45:00 Author:Ecco | Keyword: Simple, long-distance, wireless microphone | From:SeekIC

The loop antenna L1 for emission also serves as the oscillation coil, the high frequency current flowing in antenna has the same resonance with the oscillation frequency, so it is always in the best emission state. In practice, the launching distance is about 100-1850M in empty area ( receivers is a the Pocket Radio TOLY1781, and the receiver distance of antenna is added as 0.8m ), in contrast, under the equivalent working voltage, current and emission frequency, if L1 is changed by an ordinary spiral circle, oscillation transistor collector is connected to a 5PF capacitor with a 0 . 8M trolley line, the two launching transmission distances are almost equivalent to prove that the concealed shaped antenna, which is also used as the oscillator coil, has a quite high emission efficiency.



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