Multi Tube Amplifier (T446E)

Obtained in MIT documentation this circuit uses several tubes to obtain a large gain in the amplification of small signals.

Moisture Detector (CB22075E)
The basis of this circuit is an LM380 that drives a speaker that emits sound when moisture is...
Photometer (CB25982E)
This circuit was found in the November 1966 issue of Electronics Now magazine. It uses an LDR as a...
Intervalor 555 (CB24308E)
This windshield wiper intervalor was found in the July 1974 issue of Radio Electronics magazine. Note...