This commercial signal follower was found in a 1967 Japanese magazine. It uses germanium transistors and provides a speaker output without the need for a transformer.
In the figure we have the photo-conductive way of using a photocell to control a small motor with...
Pressing S1 the LED glows by a time interval depending on the capacitor. Time intervals in the...
This is a protection circuit in which, under excess current in the load, the SCR trips by shorting the...