Servo amplifier (T454E)

Found in a MIT publication from the 1940s, this circuit shows use in a servo amplifier. The supply is made with different voltages.

FM Decoder (CB4601E)
Frequency modulated signals up to 500 kHz can be decoded with the PLL we show. The demodulated signal...
Integrated Digital Circuits Test (CB3895E)
We found this circuit in an American documentation of the 80's, being indicated for the test of...
AC134 or AC126 stage (CB4267E)
This step uses germanium transistors such as the AC151, GE2, and others having been found in a...