Lie Detector (T1534E)

This circuit was found in a Popular Electronics from December 1956. Power is provided by batteries.

Voltage Controlled Zener (CB12226E)
This configuration that functions as a zener diode was found in an English publication from 1976....
Simple Capacitance Meter (CB25854E)
This circuit can measure capacitances in various ranges using a common analog indicator. The...
Low offset video amplifier (CB7144E)
Intended for amplifying analog video signals, this old documentation circuit has a 20 MHz pass...