Signal Tracer and Capacitor Tester (T1241E)

This mains powered two-in-one instrument was found in a Radio Craft from March 1948. The headphone must be high impedance.

Divider by 2.5 (CB12441E)
This circuit is from a 1991 publication. It divides the frequency of a TTL signal applied to its...
Power supply circuit (CB25185E)
By adding a transistor to the output and some polarization features we can obtain a higher output...
Sampling and Hold Circuit (CB19334E)
This sample and hold circuit was found in ancient European documentation. The operational can be...