Don't know about non-hot-wire gauges but hot-wire gauges have an impedance
of just a few tens of ohms. Haven't done any time contant calculations in a
long while but if LC = seconds then we are talking about 5,000 micro-Farads
for 1/10th sec.
PaulH.
-----Original Message-----
From: Larry Colen <lrcar@red4est.com>
To: Wildbil923@aol.com <Wildbil923@aol.com>; healeys@autox.team.net
<healeys@autox.team.net>; mgs@autox.team.net <mgs@autox.team.net>
Date: 20 August 1999 02:35
Subject: Re: Slowing the Fuel Gauge Fluctuation on an LBC
>How fast is your fuel guage fluctuating? Most guages have pretty slow
>responses (see how long it takes to stabilize when you turn the car on).
>I don't know what the resistance of the sender is but I'd guess that the
>time constant with a 100microfarad capacitor would be on the order of
>tenths of seconds, far faster than the response of the guage. It would
>have the benefit of storing a lot more energy so that if something did
>go wrong that might cause an the sender to arc it would be a lot more
>likely for you (or your heirs) to collect insurance money from the
>explosion and fire.
>
> lrc
>
>On Thu, Aug 19, 1999 at 09:13:22PM -0400, Wildbil923@aol.com wrote:
>> A very knowledgable lister suggested the following means for slowing down
the
>> fluctuation of the fuel gauge needle action on an LBC:
>>
>> >>>>>The wire in the circuit that has the fluctuating voltage is the one
>> running
>> from the gauge to the sender unit. Supposedly if you were to install a
>> capacitor in parallel with this circuit it would absorbe some of the
>> pulsation of the current and damp the needle on the guage. I think it
>> would call for a large electrolytic capacitor, probably 100 microfarad or
>> larger, with the larger capacitor doing more damping than a smaller one.
>> It could be mounted just on the back of the gauge, one wire connected to
>> the sender terminal and the other wire connected to the ground terminal.
>>
>> Keep in mind that electrolytic capacitors are polarized. If your
>> electrical system is positive earth, then ground the positive side of the
>> capacitor. If it's Negative earth, then ground the negative side of the
>> capacitor. If you get an electrolytic capacitor hooked up backwards it
can
>> explode like a firecracker (usually blows one end out) and spray wax
paper
>> and aluminum foil confettie all over the place, along with a moderate
dose
>> of sulpheric acid (battery acid). If you actually try this, let me know
>> how it comes out.<<<<
>>
>> Has anyone tried anything like this? Any comments?
>>
>> Bill Wilkman
>> Riverside, CA
>
>--
> Rome did not create a great empire by having meetings; they did it by
>killing all those who opposed them.
>lrc@red4est.com http://www.red4est.com/lrc
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