This diagram was found in the November 1972 issue of Radio Electronics magazine in an article describing benchtop equipment. The transistors are of the time and the frequencies are given by the coils.
This circuit is from an American 80's documentation. The transistor is general purpose,...
We found this circuit in the September 1971 issue of Radio Electronics magazine. The sensor is an...
This old configuration, using a unijunction transistor (UJT) controls a LED than blinks if an...