This commercial transistor tester circuit (EICO 666) is from a Japanese publication from the 1960s. The switch selects the types of test with the switching of the terminals and the gain ranges.
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...