In the 110 V network, capacitors of 200 V or more and in the 220 V network, capacitors of 400 V or more, can be tested in this simple circuit. The indication is given by a neon lamp.
This 5-transistor receiver was obtained from an article in the February 1969 Radio Electronics magazine....
Found in a 1969’s EDN, this circuit provides 4.5 V with a 100mA current for digital logic. The...
This useful power supply was found in an 1985 Italian publication, but can still be assembled...