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 circuit produces a loud sound in the speaker when water level reaches the sensor. The power...
This circuit should be used with low frequency signals only. The circuit is from a documentation from the...
This Signetics circuit uses a double 555 (556) to generate tone bursts at frequencies determined by...