Test circuit with bridge (CB22530E)

This bridge-biased transistor test circuit measures gain in the range 0 to 300. Circuit is from Radio Electronics June 1952.

Signal Follower with Old Transistors (CB12922E)
This signal follower, from a publication from the 1970s, uses old germanium transistors such as...
Photometer (CB19147E)
This sophisticated photometer that has a light comparator with LED indicator came out in an...
Fluorescent Lamps Test (CB18603E)
The presented circuit is used to test ordinary fluorescent lamps. This circuit also has a mains...