We found this circuit with the 6A6 double triode in a 1938 Radio Handbook. The power source is not provided.
The basis of this circuit is an LM380 that drives a speaker that emits sound when moisture is...
This circuit was found in the November 1966 issue of Electronics Now magazine. It uses an LDR as a...
This windshield wiper intervalor was found in the July 1974 issue of Radio Electronics magazine. Note...