This circuit activates an old cassette recorder when the phone is being used, thus making it possible to record the conversation. The circuit is from a Hands On Electronics from the 90s.
This circuit can be installed inside a toy space gun to produce a “Phaser” effect. The circuit is from...
This circuit was found in a 1988 publication. The circuit is an alarm with interrupt sensors that...
The frequency in this circuit is adjusted by P1 and given by C1. Short pulses, as the ones...