Tachometer --- waveforms ?

[Smeerak]

Hi guys and gals !

I'm building a pneumatic "tip tronic" shifting device for a motorcycle engine. part of this project involves tapping in to the tachometer line.

The bike is a Honda CBR 600 F4i ... my question ?

What does the waveform of a tachnometer normal look like? Well more specifically I'm almost positive it's an ~12V square wave but I guess my question is as RPM increase does the frequency of the wave increase ? OR as RPM increases does the voltage incresase ?

I hope it's ok to ask this question in this forum, I figure there are plenty of techies around so that's why I ask. Also I did have the opportunity to test or the tach on a real bike engine, however, well, the guy was only willing ot disconnect so much of his wiring harness so it was a no go.

Thanks !

[NDR008]

Interresting question, no one got an answer for it? would be usefull for a shift light circuit in my car.

[Guest]

the frequency of the wave increases as RPM increase
you can connect it to a frequency to voltage if you need to