Datasheet of This battery powered intercom was found on a January 1947 Radio Craft. |The circuit is 4-way but can be modified by changing the key.
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...
