Found in Popular Electronics from the 90s, this circuit consists of a timer that turns off the power of a circuit after a time determined by C1, saving the battery.
The transducer of this circuit is a small ceramic capsule or crystal earpiece and the frequency given...
This circuit was found in an American documentation from 1968. The circuit generates ladder-shaped...
The circuit shown in the figure generates a rectangular signal whose frequency depends on C1. For...