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More than Circuit EngineeringEspionage. Microphone – stethoscope
Схемы >> Espionage >> Espionage. Microphone – stethoscopeEspionage. Microphone – stethoscope
Electronic stethoscope registers vibrations of walls with the thickness up to 0.5 m. If it is necessary a signal can be amplified, by using the additional amplifier of low frequency. The sensor of vibration can be made out of the sound receiver sensor (from a record player) or are used piezoelectric vibrator, which well reproduce frequencies in a range 800-3000
Hz.
Microphone – stethoscope Circuit
Literature: Magazine Радиохобби №3 1999.
added 26.01.08 22:20:37 | 
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