I need advice for 12vdc resister for warmth

[Hooey-Doo Hollow]

I hope to replace an incandescent light bulb in a wax tart warmer with a resister. I assume a low watt and low ohm resister would work. How about 10w 3ohm resister on the 12vdc circuit?

 

[danadak]

What is output V and current of wax tart warmer ?

 

[Hooey-Doo Hollow]

What is output V and current of wax tart warmer ?

It is currently a 7watt 110vac. I want to run it on 12vdc. Not too hot, just warm to touch.

 

[Diver300]

20 Ohms resistor is what you need to give 7 W at 12 V. Use at least a 25 W rated resistor if you want that much heat without the resistor surface temperature getting too hot.

If you are using it in car, the voltage will be around 14 V with the car running. You would need 28 Ohms to get 7 W at 14 V.

 

[Tony Stewart]

you may be spreading the hot surface of the glass bulb by an air gap. Although a resistor is not as hot, when dissipating max power the surface temp will rise 125’C. This rise can be reduced by choosing a much larger power rated resistor like 25W or a heatsink then air to distribute the heat but still dissipate 7W

 

[Pommie]

Note, any amount of wattage will reach any temperature given enough insulation. Try to keep everything the same and replace the bulb with the resistor.

Mike.