# Generating heat?

I'm an electronic enthusiast (unfortunately I don't have much knowledge on the subject past basic components and volts, current, watts, etc) and I am wanting to know what the best/simplest method would be to generate heat (A noticeable amount from room temperature, at least) using a 3-12 volt (DC) source (with around 10-20A) without heating up the source or other cables (only heat up a specific cable).

A simple wire connected to both ends of the source will create heat, however it will also heat it up. I need a way to create heat without this.

Sorry for any bad explanations, I don't fully know what I'm talking about.

With resistance wire like nichrome.

Nichrome wire has a small resistance, but much higher than regular wire. Its often used to make heating elements.

To keep the heat away from the power supply, you would use regular wire at each end, with a length of nichrome wire in the middle.

The power draw and heat created depends on the length and resistance of the nichrome - it comes in different gauges with different resistances per length.

• So I simply need to have a circuit like this, where the green wire is just regular cable, and the coiled orange wire is Nichrome (or some other conductor with similar properties)? Or am I missing something – Karl Feb 21 '15 at 0:17
• Yep, exactly like that. You will have to calculate the appropriate gauges of wire and resistance of the heating coil to get the power draw and heat you want. – Grant Feb 21 '15 at 0:20
• any idea where I can find some details on how to calculate that? – Karl Feb 21 '15 at 0:23
• @karl Ohms law and the specs of the nichrome wire. The resistance you need to draw a given current is Volts/Amps. – Grant Feb 21 '15 at 0:29
• Thank you so much for spending your time to help me solve my question. – Karl Feb 21 '15 at 0:31

Look at how any kitchen heating appliance, such as a toaster, is built. The connections to the wall outlet are made with relatively large-gauge copper wires, which have low resistance, and don't get significantly hot. On the other hand, the heavy nichrome wires inside the toaster, which have higher resistance, get red hot.

The same current is flowing through all of the wires, so the heat dissipation and temperature rise is proportional to the resistance.

This specific problem is common with people who are building heated beds for the 3d printers. You can find nice solutions that will work exactly in the range you specify (12V @ 10 Amps), some are flexible mats, and some are printed circuit boards.