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.

Stereo balance indicator (CB8509E)
Found in a 90s Popular Electronics, this circuit uses a simple 9 V source. The power can be used...
Electronic injection (CB12933E)
Originally the circuit in the figure is indicated by National for the control of an electronic car injection...
Micro MW Receiver (CB16436E)
This simple receiver that works with only 1.5 V, was found in a 1987 documentation. The integrated...