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.

3 kHz Notch Filter (CB13567E)
We found this circuit in a publication on operational amplifiers from 1978. The circuit is made...
Light intensity meter (CB7340E)
This circuit was found in a Philips documentation from 1970. The components are of the time,...
Bandpass Filter (CB6731E)
Found in a 1967 documentation this circuit can be applied to any operational amplifier. Components...