Diode Tester (CB22137E)

This diode tester was found in an English publication from the 1980s. Transistors are general-purpose types of the time.

Cascading in 4013 (CB153E)
A binary counter until 2" or a divide-by-the same value can be built by cascading n 4013...
Digitally Controlled Oscillator (CB18268E)
We can control the frequency of an oscillator from digital circuits or from the output of a...
Field Strength Meter (CB6538E)
Found on Popular Electronics this circuit has variations found throughout this site and section....