This 4-tube counter was found in Radio Electronics magazine from December 1959. The circuit uses a coil as a sensor to detect the passage of metallic parts or magnets.
In this circuit, the current capacity doubles, but is still of the order of microamps. The...
We found this oscillator in an integrated circuit manual from the 90's. The circuit shows how to...
This regulator can be controlled by a logic signal. The circuit is from an Electronics Now from...