PLL (CB7971E)

This common operational PLL circuit was found in a Popular Electronics 90’s. The power supply need not be symmetrical.

OR and AND function (CB19889E)
In this circuit, which uses only diodes, we have both simultaneous functions. The diodes are...
Universal Logic Tester (CB24671E)
This logic tester circuit was published in the November 1980 issue of Radio Electronics magazine. The...
4-way logic test (CB8908E)
This circuit was found in a 90s Popular Electronics. The circuit uses 4 bicolor LEDs to indicate...