RF Spy Bug Detector Circuit. May 23, 2013 by P. Marian Comments 8. Advertisement. ... The sound is amplified by A4 section and then is applied to a 8Ω/0.5W speaker. Use a telescopic antenna that can ...

This photoelectric smoke detector circuit uses one LED and 2 LDRs to detect the smoke and sound an alarm. The LM1801 IC is the best choice for this circuit because we need a few external components ...

Scientists have demonstrated a new kind of detector for sound at the level of quietness of quantum mechanics. The result offers prospects of a new class of quantum hybrid circuits that mix ...