With this circuit it is possible to use a frequency meter as a tachometer. The circuit was found in American documentation from the 90s. The phototransistor can be of any type.
This single-channel remote control transmitter operating in the FM range uses common components and...
This circuit was obtained in a 70s American documentation. The integrated circuits of the time are...
This voltage sensor limits the discharge of a Nicad battery. We found it in an American...