Peter :
Yes, I think it's just coincidence the readings match. The DMM is counting
the multiple zero crossings as the primary of the coil 'rings' after each
spark. The ratio of true to apparent reading will probably also change as
the speed changes.
You could try building a simple shaping network, by putting a resistor (10K
?) across the meter leads, and a couple of diodes in series to the coil.
Seems like that should help, but I haven't tried it. Perhaps when Dan
Masters gets back, he'll have a "tried and true" circuit.
Randall
59 TR3A daily driver
> -----Original Message-----
>
> Is it possible I just have the right set of circumstances
> whereby my tach
> and DMM "agree".
>
> Note: I think my tach is reasonably accurate.
>
> --- Peter Zaborski CF58310UO ---
>
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