>Can someone explain to me the theory of electronic tach operation and all of
>the components involved so I may begin to troubleshoot this problem without
>having to buy all new parts in a process of elimination?
>
>Any help would be appreciated.
>
>Mike
>79 Spit
Mike,
As I understand it......(right or wrong is for you to decide!), an elec.
tach. works by sensing the number of ignition pulses on the LT side of
the ignition. when it has a number of pulses to sense, it first
multiplies that number by two (for a four stroke engine, only every
other stroke has an associated ignition pulse), and then divides it by
the number of cylinders you have.
How it actually translates this to a needle movement is done with
electromagents I think, so your guess is as good as mine beyond this
point.
all of this is kind of theoretical, as all you ever see is a moving
needle, but this is how it would be calculated if it were to be broken
down to pure electronic terms, in the real (Triumph/early British cars)
world, its more likely to be a piece of string going from the flywheel
to a greasy barrel in the back of the tach, the more you rev, the
further the needle moves. Does that sound about right?
just my theory on how to simplify electonics....
Kevin.
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