Voice Scrambler (CB22462E)

We found this circuit in a Popular Electronics from 1992. It consists of a voice scrambler used in telephone transmissions.

Stabilized Power Supply from 0 to 24 V x 1 A (CB12898E)
This power supply, found in an Argentine publication from the 1970s, uses a wire potentiometer of 25 W or more...
Power inverter (CB22504E)
We found this circuit in a publication from 1966. The components are from the period. Complete...
Crystal Sinusoidal Oscillator (CB5129E)
Found in an 80's documentation this circuit uses an integrated from the uncommon era today. Other...