This circuit with a differential pair was found in the August 1974 Radio Electronics magazine. The frequency is determined by L1 and the variable capacitor.
This electronic roulette circuit with 10 numbers was found in a Popular Electronics from the 80s....
This circuit has a very high input impedance and a very low output impedance. We found it on a...
This circuit is from an English documentation from 1969. The circuit can be designed based on...