This circuit was obtained from a 1947 amplifier manual. The circuit makes use of a transformer source, but it can also be battery powered.
A tap on sensor X1 of the circuit shown in the figure causes the flip-flop formed by the 4 NAND...
This circuit, from Intersil Databook since 1983, shows the use of the ICL7107 in a voltmeter with...
I got this4 circuit from Hands-On Electronics, 1988. The American magazine no longer exists, but...