Another simple way is to put in a miniature panel ammeter so you can
actually see the current used. I got one of them (real tiny) for my
inflight adjustable IVO prop so I can tell when it is at extremes. More
info on the tiny panel ammeter at http://www.abri.com/sq2000/hints.html
Would be a much simpler circuit and probably safer.

iflycozy wrote:
Question to you electrical designer gurus:

Here is what I would like to do and Jim Wier suggested that I post this
here. I want an indicator on my Cozy homebuilt airplane to show me
that my heated pitot is actually working when I turn on the switch on
the instrument panel. So, the light will go out (with the switch still
in the on position) if the heated pitot stops working for some reasons
(but not because it tripped the circuit breaker). So, how can I build
such a device or circuit? I would appreciate specific parts or
identification of parts as I am an amateur. This is a 12 volt DC
system and the heating element draws 7 amps. I know I can not use a
LED in series because it would blow the milli-second I turned the unit
on. I know I can't use a light or lamp in parallel because it would
not indicate if the heated pitot was on or off. So that is my dilemma.
Please help.

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