Re: 12v to 6v drop down resistors
Using Ohm's law, V = I R or R = V/I, to get a 6V drop across the resistor if your horn uses 6 amps current, R = 6/6 = 1, so, you want a 1 ohm resistor (adjust accordingly for whatever current, I, your horn draws.
The power dissipated by the resistor would be I-squared x R, or, for this example, 36 x 1 = 36 watts. Probably could get by with less, unless you're planning on continuously laying on the horn or the resistor is going to be located with no ventilation.
The wiper will require a lot less.
Last edited by steve s; 08-20-2013 at 08:22 AM.
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