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How to drive a 12v 40w heating pad

punkieys17

Feb 7, 2016
45
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Feb 7, 2016
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My wife asked me to make a honey heater. They are normally pretty basic with a wooden box and 2 40w light bulbs. However when our desktop washing machine broke I grabbed the opportunity as its a ready made cabinet. I found a really cheap 240v thermostatic controller with temperature probe and bought 4 40w silicone heating pads. I now need to drive the 40w heating pads. Is there any reason I cannot use the small transformers used for driving house halogen spot lights - they are often rated 25-65w and are relatively small. Even better as people convert to LED lighting you can buy multiples really cheaply. Any reason what the load from a silicone heating pad would not be compatible with halogen 240v to 12v transformers?
 

kellys_eye

Jun 25, 2010
6,498
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Jun 25, 2010
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6,498
If the transformer can deliver AT LEAST the current required by the heating pads (being able to deliver MORE current is better as this puts less strain on the transformer) then there is no reason you can't use them.
 

Bluejets

Oct 5, 2014
6,864
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Oct 5, 2014
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If the "transformers" you refer to are around 250mm long and rather heavy (the old iron core transformers) then you are ok.

If they are the more modern switchmode type used for LEDs perhaps only half that size and very light, then forget it as they are current regulated.

Best when you post to include ALL details such as photos.
 

ramussons

Jun 10, 2014
462
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Jun 10, 2014
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462
Do you have access to a spare computer PSU? That will do fine.
 
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