Found in Popular Electronics from the 90s, this circuit can be used in tachometers. The integrated circuit is not a common component today.
This is the circuit of a “follow the line” type robot with inductive sensors published in Radio...
With a unijunction transistor and a tunnel diode it is possible to obtain rise times of 1 ns with...
This receiver for listening to headphones and 2-battery power was found in Japanese documentation from the...