This circuit triggers an alarm in the event of a power failure. The circuit is from an 80's documentation, being powered by 9 V battery. The parts are common today.
This microphone preamp allows the use of high impedance crystal microphones with amplifiers that have...
This is the radio receiver for the previous infrared alarm radio transmitter. It contains the...
This amplifier for a sinusoidal function generator uses a 741 integrated circuit. The circuit is...