5 ms·
And by "fairly hot", you might use as an example the tungsten filament in a Christmas light bulb - which can be 2500 C! Power (and therefore heat) is current s
by LeifCarrotson 11y ago
And by "fairly hot", you might use as an example the tungsten filament in a Christmas light bulb - which can be 2500 C!
Power (and therefore heat) is current squared times resistance, or equivalently voltage drop times current. A copper wire or PCB trace has very low resistance, and a soldering iron tip or thin tungsten filament has high resistance, so one stays cool while the other gets hot.
- collyw 11y agoOk, thanks for clearing it up. I had kind of assumed PCB trace would have some resistance due to the relatively small size of it (compared to say a cable on an electric appliance), but I guess the heat is coming from the soldering iron tip and doesn't need to be huge to get it hot.