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.
In the figure we have a circuit with two operational amplifiers 741 capable of doubling the...
What differentiates this circuit from the previous one is the need for a much smaller current to...
This circuit was obtained in a Maxim documentation from the 90's. The circuit applies to...