Potentiometer

sphanna

sphanna

Well-known member
I would like to find a rotary poteniometer to put in line with the horn power. I have a 12 volt system and a 6 volt horn. Really makes the horn loud and higher pitched and I want to continue to use all 12 volts in traffic but control voltage to adjust to normal sound with 6 volts. I thought I could use a fan speed control from hardware store but I could not get power through the controler to the horn. Haven't understood why yet. Anyone know what I should get to accomplish this. I do not just want a resistor that would drop the voltage to 6, as the horn may work best at 7 or 8 volts. I want to be able to vary it.
 
I think such out of an old hotplate, electric heater, or oven might work. They are usually a resistive wire coiled and nestled into a chunk of ceramic with a rotary knob and contact. I have no idea what the resistive values are and the range of motion that gets you where you want to be may be tiny so you would have to experiment. If you have access to used lab equipment there would be even more choices.
 
This is what you need: Ohmite RKS2R0
RKS2P0.jpg
 
I tried to make my own resistor so horn would not burn out on 12 to 6.

No luck.

Was successful in making a resistor for starter motor tho.
 
pooch: I believe you could have fed 12V to starter and it would have been all right. Others may correct this info though.
Paul in CT
 
I was warned off using full current 12 volts on an early 1/2 inch starter.

Was good advice.
 
RE: Potentiometer
Thanks for all the replies. I looked up the recomendation by MikeK. I am wondering the amps that the horn draws. Volts times Amps = watts. Therefore I am wondering what mim. watts capacity I need. 12X8 = 96 Do I need a 100 watt max load resister if for example the horn draws 8 amps? Perhaps an electric heater control would work?
 
sphanna said:
RE: Potentiometer
Thanks for all the replies. I looked up the recomendation by MikeK. I am wondering the amps that the horn draws. Volts times Amps = watts. Therefore I am wondering what mim. watts capacity I need. 12X8 = 96 Do I need a 100 watt max load resister if for example the horn draws 8 amps? Perhaps an electric heater control would work?
Click to expand...

What Mike showed should be the perfect solution!

A good working horn uses about 5 amps on a 6 volt battery.
 
Some of the 6 volt automobile heaters had a knob type switch that included a voltage reducer in the switch,maybe 12 volt switch had this too. rotating the knob made it run faster or slower depending -- . more like a resistor I thought .They had protection around 'em to Keep your fingers away so you wouldnt get burned.
 
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