This 100 kHz oscillator was found in a 1966 Motorola publication. The transistors are of types suitable for the generated frequency and L1 / C1 depend on that frequency.
This 1967 Raytheon circuit uses an optical coupler of the era and has a range of 800 to 200 Hz....
This interesting digital counter with relays with complementary outputs was found in the Radio...
This circuit uses a diode as a radiation sensor. The operational ones are old because the...