Bike speedometer (CB20497E)

This circuit can be powered by a solar cell. The circuit is from a 1991 documentation having a phototransistor as sensor.

3 W FM transmitter (CB18765E)
This circuit was found in a documentation from the 90's. Power is included, and the regulating...
Doubler from 150 to 300 MHz (CB4870E)
We find this circuit in the 80s used integrated circuit manual itself. The integrated circuit is not...
Current-controlled oscillator (CB21648E)
This sweep generator or current-controlled oscillator was found in Popular Electronics from...