Very very electrical question., Tachometer waveform Options

[sgomes]

Ok, I don't expect to get an answer to this question but here goes nothing:

I've got this fancy tacometer drive thingy that is supposed (IMG:style_emoticons/default/unsure.gif)

Assumptions about the tach:

It expects at least +5V pulses more is ok.
It assumes a four cylinder engine.

My assumption on how tachs work:

You get one pulse for every spark. So.....

assume 6000rpm for the sake of argument
6000rpm= 100 revs per second * 60 seconds
4 sparks per revolution.
4 * 100 = 400 pulses per second.

I've got something close to 200 pulses per second comming out of my sender at about +10V.
The tach isn't moving.

[BIGKAT_83]

After I converted my 74 914 tach for a V8 operation I calibrated it with a function generator that produces a square wave siganal and it worked fine.
I tried using the same square wave generator on a early tach and it did not work. I just assumed that the early tach was bad.

SGOMES........If you need a later tach PM me I've got them laying around everywhere.


Bob