Sawtooth generator (CB21338E)

This op amp circuit is based on a 555 IC and two common op amps. Transistors are general purpose.

Fuel Low Warning (CB24111E)
This circuit was found in the April 1971 Radio Electronics magazine. It uses common transistors and can...
Telephone Scrambler (CB23524E)
This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963....
Ladder Generator (CB21245E)
Using a 4017 as a base, this circuit from a 1990s Popular Electronics generates low-frequency...