Switch with automatic shutdown (CB21258E)

This circuit was found in Maxim documentation from the 1990s. The RC circuit determines the trigger time.

Electronic Crossover (CB20648E)
This circuit separates the bass from the treble in an audio signal. The circuit is from a Hands On...
Car Sound System (CB17339E)
This circuit was obtained in a 1986 documentation consisting of an active frequency divider for...
Voice Scrambler (CB22462E)
We found this circuit in a Popular Electronics from 1992. It consists of a voice scrambler used in...