Lie Detector (T1534E)

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

Rail to Rail Oscillator 555 (CB9099E)
Found in an Electronic Design from the 80s, this circuit generates a 500 Hz signal and can be used...
TTL Isolator (CB14047E)
This circuit is from the 1972 RCA Linear Integrated Circuits Manual, but it can be made based on...
Simple Power Control with Diodes (CB11971E)
At each switch position, a diode is connected in series with the motor, thus causing a small...