Horn - voltage reducing resister

[Jon-Ohio]

Was wondering what size (ohms and watts) resister is needed to drop 12 volts to 6 volts for a Model a horn ? Would like to get one locally instead of the hassle (and high cost) of ordering one from a parts supplier.

Thanks - Jon In Ohio

 

[steve s]

I just grabbed a big one out of my junk resistor box and it worked ok.

Let's see if we can figure it out:

You want a 6 volt drop E across resistance R for about 6 amps of current I.

E = I R or R = E/I = 6/6 = 1 ohm.

Adjust to suit your horn's current draw. It helps to have a few extra volts for the horn for use at idle or low speeds.

Power equals current-squared x resistance, which for above calculation indicates a 36 watt resistor (or larger). I think you could get away with lower rating as long as you don't blow the horn continuously--give the resistor time to cool down.


Steve

 

[jrelliott]

On Ohmite RKS2RO or go to www.studebaker-info.org/tech/6-12V/6-12-6.htrr for an electronic voltage regulator

 

[BILL WILLIAMSON]

Somewhere, I read, that a "hidden" ignition coil makes a good horn resistor?? Bill W.