Lie Detector (T1534E)

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

Timer with Relay 14538B (CB18466E)
This timer, like the previous circuits, uses a currently uncommon integrated circuit. The time is...
Polarity Indicator (CB17589E)
This circuit indicates the polarity of a voltage applied to the input. The circuit can make use of...
Magnetic Transducer Amplifier LM139 (CB14230E)
The circuit shown below was found in the National Semiconductor Linear Applications Handbook...