Diode Tester (CB22137E)

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

Word Filter (CB13612E)
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...
Voltage Doubler (CB20196E)
In the figure we have three voltage doubler configurations that can be used in high and low...
Ring Counter using Lamps (CB6599E)
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...