Modulated light receiver (CB21790E)

We found this circuit in a Mullard manual from 1960. The transistor is a phototransistor of the time. The gain is 3 dB.

Extended range power control (CB7935E)
This circuit was found in a General Electric documentation from 1965. The circuit is full wave for...
Null Detector (CB11550E)
We found this circuit in the Texas Instruments' Linear Circuits Applications. It uses an...
Operational Variable Astable (CB14827E)
In the presented circuit it is possible to vary the frequency of the rectangular signal produced. This...