This circuit was found in an ancient American documentation. The power supply is not given, but we have the voltages used. The relay is sensitive type for high voltage.
The indicator instrument of this transistor tester, from an Argentine publication of the 1970s,...
This simple 555 component tester was found in the November 1992 issue of Radio Electronics...
This circuit can use both separate LEDs and a common cathode display when one segment indicates...