Wattmeter (T1351E)

This circuit is from a February 1949 Radio Electronics magazine. The circuit uses 3 tubes and includes the power supply.

Pulse Extender (CB12390E)
What this circuit does is to stretch a pulse, increasing its duration. The integrated circuit is...
Picoammeter (CB9661E)
This circuit is designed to measure very weak currents, in the order of picoamperes. We found it...
Comparator with indicator lamps (CB9584E)
Found in an American documentation from the 90s, this circuit uses small low voltage lamps (6 to...