PCB Heater

The idea

I got the idea to draw a serpentine pattern on the unused area of a PCB, and to test how much heat I could produce with it before melting the tracks. On the left, you can see what it looks like. It has a 3.6 ohms resistance.

I think this PCB could be used for "useful" applications.

  • Keeping a coffee cup hot (by placing the cup on the pcb)
  • Keeping a device warm enough to work properly (if it has to be outside during the winter).

Note: I know that there are better and more reliable ways to generate heat. I did this experiment mostly for fun.


I first tried to heat the PCB using my bench power supply, which is able to regulate current. It has not been too long until I reached the maximum current the power supply could provide. 3 Amps were flowing through the PCB, and it was quite hot.

Next, I decided to try something else: Boil Water with the pcb. I filled a container with water, and inserted the PCB in the water(see picture):

Of course, it was necessary to use a more powerful source of current than the previous one. I used my 10 Amp Variac, connected to the mains. I installed my ampmeter in the circuit, and raised the voltage progressively.

Warming up...

Warming up...

At first, I was very careful not to raise the power too quickly, in fear of melting the PCB tracks. On the picture on the left, there had been 5 Amps flowing in the circuit for several minutes. The water was getting hot, but not boiling.

Finally, I raised the current up to 8 Amps. A few moments later, the water was boiling. I could hear a 60hz hum coming from the variac too...

Finally boiling

Finally boiling


I cannot be held responsible for any damages that could occur to you or your equipment while following the procedures present on this page. Also, I GIVE ABSOLUTELY NO WARRANTY on the correctness and usability of the informations on this page. Please note, however, that the procedures above have worked in my case without any damages or problems.

Now you cannot say that I did not warn you :)