Spy Telephone Circuit

Posted on Feb 7, 2014

This FM spy telephone circuit is mounted serrial with the phone line. When is signal on the wires this transmitter will radiate airwaves thru the wires wic..

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Watson Oct 10, 2017

Thais circuit does not have a Zener diode to protect it against excessive voltage. The 6 to 9 volt Zener should be across the supply to limit the voltage. This circuit must be connected in series, where the phone line enters the house from the street. Thanks.

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