This circuit makes use of a low impedance microphone. The relay is according to the supply voltage which can be between 9 and 15 V. The operational gain is approximately 100.
ROHM Semiconductor is featured in a new line of IR LEDs, Proximity Optical Sensors and Ambient...
Found in a documentation by Hugo Gernsback from 1960, this receiver uses germanium transistors of the time...
In the figure we have the way to connect several 555 to obtain sequential operation. The component...