Null Indicator (CB21930E)

This bridge was found in a Raytheon transistor manual from the 1960s. The transistors are germanium from the time.

Delayed Alarm (CB1511E)
This circuit was found in a 1977 Signetics manual. The 556 consists of a 555 double and the...
100 mW transistor amplifier (CB22521E)
One of the first transistor amplifiers with transformerless output but using a 45-ohm speaker. This...
VHF to AM converter (CB16829E)
With this simple converter found in a 1997 documentation, it is possible to tune VHF stations to a...