I have a question about measuring the frequency of the output of a synchronous generator (3-phase, wind turbine).
The generator is not running yet but I think the voltage will vary between 0-58V (I have a charge controller that regulates the voltage, ~48V when charging batteries and 58V when dump load is active )
My idé is to use one diode as a rectifier and a zener diode to get a regulated voltage. To isolate the MCU I thought a optocoupler would work.
I have never used a optocoupler before and don’t know the minimum current to get it working.
I have tried to read the datasheet (http://www.vishay.com/docs/81181/4n35.pdf) but is not sure what to look for.
Where can I see the minimum voltage requered, is it picture i4n25_06? Then 0,5mA is not enough?
Is the zener diode in my circuit unnecessary? (se attached picture)
Properly you know a much better way to measure the AC frequency!