Common gate stage (CB7470E)

This circuit for FET was obtained from a 1977 Radio Handbook. The input impedance is 150 ohm. The output is high impedance.

Optical control notch filter (CB6717E)
This 1967 Raytheon circuit uses an optical coupler of the era and has a range of 800 to 200 Hz....
Even and odd counter (CB23780E)
This interesting digital counter with relays with complementary outputs was found in the Radio...
Dosimeter (CB5922E)
This circuit uses a diode as a radiation sensor. The operational ones are old because the...