I believe it puts out a peak 14V AC sine wave (which means ±7VAC?), 1190Hz @ 5000rpm and ~200Hz at 850rpm.
That being said, all you need to do is add a 1k resistor from pin 5 of the 4N35 to the arduino +5V and then the analog pin will read voltage.But do you really want to measure voltage ?Is there any doubt that the voltage you measure is going to be 5V (correct answer: no)
how on earth you arrived at 1190Hz will be interesting to learn
A tachometer converts mechanical power into a small electrical signal for measuring rotation speed - yet youtalk of "driving the tachometer" from an alternators W terminal?Do you mean you are trying to drive a tachometer's meter unit? IE replace the tachometer with a different signal source?
I was going based off of this post's frequencies, I figured the frequency was what came from the alternator's W terminal.https://www.vwt4forum.co.uk/showthread.php?t=453463
What guage ?
Where did you get that diagram from.It won't work.Voltage swing on the emitters of the NPN/PNP pairs is 0.65 to 4.35volt (emitter followers).Impossible to drive mosfets with that.Are you trying to do something like this?Leo..