Indicators

[redzer]

I recently decided to replace the dash lights on my spitfire with led ones and now because led's are sensitive to polarity the dash indicator light will only work when you indicate in one direction, swap the terminals and the indicator will work for the opposite direction.
is there a relatively easy way to have one led work for both left and right or are 2 led's needed.

Tony

[oldbanger]

would putting something like this in the circuit help ???

http://en.wikipedia.org/wiki/Diode_bridge

:)

[rotoflex]

Léon Guyot replaced his white illumination bulbs with LED's, but I don't know if he replaced the turn signal indicator.

[CharlieB]

You just need two diodes & wire them like this:
(old circuit above, new below)

[CharlieB]

Alternatively use a solid state flasher unit with an output for the dash warning lamp.

I don't think you can use an LED for the ignition warning lamp without a resistor as it effects the operation of the alternator?

[redzer]

Thanks for the replies, in my ignorance i thought it would be as simple as changing the bulbs,
so it looks like it is possible to get the indicator warning light to work with a rectifier or a diode arrangement.

How would an LED ignition warning light affect the alternator ? i dont want to kill another alternator  :)

[junkuser]

Power through the ignition warning lamp is designed to supply direct current to the alternator for field excitation. (magnetic field to get things going).
In fact there is usually sufficient residual magnetism to get things going without this help.
I have seen Bosch rigged without it and there is a Denso circuit that does not use powered field excitation for start up.
Suppose it is a belt and bracers approach by the designers as soft iron is used in alternator/generator cores in an attempt to avoid residual magnetism and allow rapid field reversal.

Probably best to just stick to incandescent indicator lamp for peace of mind but would be interesting to hear from anyone who has tried LED for the purpose.