# Power increase

#### Alondonboy

Joined Apr 28, 2024
3
I'm using a wire foam cutter where the bridge wire heats up on a low DC voltage but it is not getting hot enough. The unit is 240v converted to 5v in a plug in transformer which simply runs up to the cutting wire. the wire was 0.23mm gauge and I've tried 0.21mm, expecting the resistance to be more, thus creating more heat, but there seems to be no change. looking for a cheap solution as once done with it will be binned.

* Should maybe add the power output is 2a and the wire cutter is 8.7w.

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#### ElectricSpidey

Joined Dec 2, 2017
2,879
You have to decrease the resistance at the same voltage to increase the power. (heat)

#### Alondonboy

Joined Apr 28, 2024
3
Decrease the resistance? I was thinking the resistance was creating the heat therefore more resistance more heat, same as with using underrated wire.

Joined Jan 15, 2015
7,570
Decrease the resistance? I was thinking the resistance was creating the heat therefore more resistance more heat, same as with using underrated wire.
Well figure it this way. Look at the relationship between Voltage and Current with Resistance. Your wire has a fixed resistance so that doesn't change. Let's call your hot wire 2.0 Ohms. The only way to increase the heat is to increase the current through the 2.0 Ohm load. If we increase the voltage with the fixed load resistance the current will increase proportional to the voltage increase. Apply Ohms Law. Your wire resistance can't change unless you use a lower resistance wire or you make the hot wire shorter. That only leaves increasing the applied voltage.

Next, consider your power source needs to be able to deliver enough voltage and current to your load, the hot wire. Consider also as your hot wire gets hot the resistance of the wire will increase.

Ron

#### ElectricSpidey

Joined Dec 2, 2017
2,879
Decrease the resistance? I was thinking the resistance was creating the heat therefore more resistance more heat, same as with using underrated wire.
Well, you can think anything you want.

Power is voltage times current expressed in watts.

Therefore, if you decrease the resistance, you increase the current.

Since you have a fixed 5 volts the only way to increase power is to decrease the resistance.

The alternative as stated by Ron is to increase the voltage.

#### MisterBill2

Joined Jan 23, 2018
19,337
Well, you can think anything you want.

Power is voltage times current expressed in watts.

Therefore, if you decrease the resistance, you increase the current.

Since you have a fixed 5 volts the only way to increase power is to decrease the resistance.

The alternative as stated by Ron is to increase the voltage.
The explanation left out only one thing, which is that it is the POWER that makes the heat. More specificly, it is the power in the wire that heats the wire.

#### Alondonboy

Joined Apr 28, 2024
3
The explanation left out only one thing, which is that it is the POWER that makes the heat. More specificly, it is the power in the wire that heats the wire.
This is why I thought if you can't increase the power to make more heat you could reduce the wire gauge to increase it? Found an old 12v power unit with a viriable supply dial so will try that tomorrow. If it burns out the wire then I guess I will have to recalculate what I can use and buy some more.