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 receiver was obtained in a documentation from the 90's and is of the super-regenerative type....
This circuit couples 600-ohm signals to a line of the same impedance consisting of an amplifier stage....
The circuit presented is from an old magazine having been translated and published in a national...