At 04:28 PM 11/22/97 EST, you wrote:
>Hi Ross,
> Would your Zener Diode idea serve to replace that line voltage
>stabiliser that's supposed to ensure reliable and accurate reports by the
>fuel gauge?
> I ask, because the gauge reads about 3/8 tank low, the stabiliser is
>new, and the WS manual says to test for 10v, with special equipment.
>Would a Zener Diode provide a constant 10v?
> BTW, I estimated that the life of the 7.5v bulb would be about 1/10 of
>the rated-at-7.5v life of 1000 hrs. How does that compare to your
>calculations?
>Bob
Hi Bob,
I don't have any reference material at hand right now but I don't know if a
zener is available for exactly 10 volts. Besides, as I understand it the
voltage stabiliser is supposed to provide a constant known voltage to
prevent instrument readings from varying with system voltage / load. A
solid state voltage regulator is perfect for this. I haven't played around
with one in this application but it certainly bares looking into. They can
be had for just a couple bucks, come in a wide range of fixed output
voltages and adjustable models are available. I'm going to look into this
as soon as I get a spare minute to pour over my wiring diagram.
As far as the life of the lamps goes, well I didn't do any calculations
specificly for lamp life. ( thats a pretty hit-or-miss kind of thing and
would only give an approximation based on the average lamp) However, if one
were to run the 7.5 volt lamps at full system voltage (14VDC) they'd be
producing @ 5.2 W each instead of 1.5. I think that an average lamp life of
1/10 rated life would be ahhh, optimistic. Of course the lower you run the
voltage to the lamps the more their life expectancy would improve. Ever
read the label on a Long Life household lamp? They're usually rated at 135
Volts, feed them at 120 and they're going to last a while.
Cheers,
Ross MacPherson
1947 MG-TC 3528
1966 MGB-GT
|