We found this circuit in the February 1983 issue of Radio Electronics magazine. The 4-digit circuit is based on dedicated integrated circuits of the time. The power supply is not shown.
This powerful source was obtained in an American documentation of the 80s. Some components are...
This simple transistor tester was found in a Japanese magazine in 1967. It tests general purpose...
This transistorized astable for LEDs was found in the January 1992 issue of Radio Electronics...