This simple transistor tester was found in a Japanese magazine in 1967. It tests general purpose transistors of both the NPN and PNP type and is powered by 4 batteries (6 V).
This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics...
The frequency in this circuit is adjusted by P1 and given by C1. Short pulses, as the ones...
This Hartley telegraphy oscillator operates with the transmitter signal generating a tone in a...