Testing of thermistors and SCRs (CB21391E)

This circuit was found in an old American manual. It is intended for testing SCRs and thermistors using indicator lamps.

Bistable (CB22280E)
This flip-flop or bistable was found in a publication about transistors from the 60's. The circuit...
Phono preamplifier LM387 (CB24941E)
This preamplifier circuit for magnetic cartridges was found in the March 1986 Radio Electronics magazine....
100 kHz Oscillator (CB21556E)
This oscillator was found in a book on transistors from 1954. The transistor is from the time, and...