Found in an American documentation from 1969, this astounding circuitry makes a relay operate on 3 Hz cycles. The relay is of the high voltage type of the time.
The correct connection of speakers and tweeters in a speaker to obtain better sound quality,...
The operational amplifier of this low current source may be any of the JFET type. The output...
This circuit was found in an old neon lamp applications publication. The relay must be in...