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.

Voltage Stabilizer 741 (CB15402E)
This circuit can supply voltages from 0 to 12 V with currents up to about 5 A, with the adjustment made...
Piezoelectric alarm (CB8970E)
This circuit is from the 80s. The integrated circuit used is uncommon as is the transducer....
Transformerless Power Supply (NI003E)
This power supply is indicated to power small loads up to 30 mA. The original output voltage is 6...