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.

Reply to:




I would use an ammeter as the most simple solution.

If you must have a light, it must be something that senses current
because current is what generates the heat, and you want an indication
if your heated pitot is working.

There are some simple circuits that would allow you to turn on a light
when current is flowing in a circuit. You will need to put a sense
resistor in the circuit.