This circuit was obtained in an American documentation from the 90's. The circuit can be implemented with some equivalent components, such as transistors and TTL logic circuits.
This precision speed control was obtained in an Electronic Design from the 90's. The output final...
Using the name of varactor this circuit was found in the Radio Electronics magazine of July 1982....
This trigger circuit was found in an American documentation from the 1980s. The amplifiers used...