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.

Optical communication transmitter (CB7849E)
This circuit was found in a 90s American documentation. The circuit uses an LED that can be of a...
Damped Oscillator (NI012E)
Damped sine oscillations can be produced when short pulses are applied to the input of this...
50 W amplifier TDA1514A (CB15371E)
We found this circuit in the Philips integrated circuits manual of 1990. The circuit must be...