This common circuit is from September 1984 Radio Electronics. The transistors are general purpose, and the frequency is given by the capacitors.
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...