>...
> The idea with intrinsically safe instruments is that the complete instrument
> would be immersed in the explosive atmosphere, where it must not cause
> ignition under any circumstance. Generally this means that currents are
> limited to a few mils, voltages are less than about 40v and capacitors and
> inductors are limited in size to minimize energy storage.
>
> In a previous life I designed "smart" pressure transmitters for application in
> natural gas applications (explosion proof rather than intrinsically safe) but
> didn't keep much technical info when I retired so can't give reliable values
> for ignition points and component values.
>
> Regards, John A044
What do you think of the capacitive fuel gauge designed by Jim Weir at
http://www.rst-engr.com/jwbib.html?
It is quite simple, and should be pretty accurate. The maximum power in the
system is at 5V and a few mils, so it should not spark.
Brian
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