Tachometer Bench Tester

Hello all

I want to build a tachometer bench tester for VW MK2 Golf tachometer. My understanding of the mk2 golf tachometer it is driven by the negative signal from the coil.

I have looked at the various sketches/circuits available on forum.

One idea was based from a car forum to use a relay coil as an inductor.

Any help or guidance would be appreciated.

Thank you

Hello
Are you shure ?

Not sure why you would want to do this unless you are setting up a business to test tachos

Hmmm … the problem is , if it works with your relay , will it work on the car ? Maybe, maybe not …if it didn’t work is the tachometer faulty or your circuit ?

I think you need to be switching a real coil which needs a transistor that can stand the high voltage generated . If I was doing it I’d google “ electronic ignition”. - recall making transistorised ignition back in the 1970’s , but sure what I used back then

Have you tried the 'relay coil as inductor' and transistor switch method? Just hook it to an Arduino pin and use the 'tone(pin, frequency);' function to send it a test signal. I'm thinking any 12V relay coil will do.

Hi,
Have you actually tried the circuit?

Tom... :smiley: :+1: :coffee: :australia: