this post was submitted on 15 Mar 2025
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Shoudn't it be 25%?
Current is not controlled here, resistance (aka the soldering iron) and voltage are.
Power = Voltage ^ 2 / Resistance. Double the voltage, that quadruples the power. So you only want to plug in 25% of the time to get the equivalent power of 120V.
But it might not melt at double power? Maybe the extra heat helps, I can't find a resistance/temperature curve for a soldering iron...
Source: EE dropout.
Ok. I was acountless on lemmy for a long time, your comment made me finally register. Thanks!
So, yeah, with double the voltage you get 4x the power. But you you put 4 times the power at 50% of the time, you get only 2x the power. And the other half of the time, you get 0 power. On the average you get the same power output.
You double counted there.
You said 4x power 50% of the time and then said “the other half of the time.”
So you’re calculating 50% of 50% which is 25% duty cycle.
Oh no, I didn't. Should I draw a graph? Pop out some equations?
Let's say P is the nominal power. When I said "The other half" I meant when the solder iron is not plugged. So:
50% of the time at 4xP 50% of the time at 0...
Oh shizzzz, you're right!
I imagine this is more or less what it felt like to be in the room at the time. A whole group of people discussing electrical theory and optimal soldering techniques and meanwhile the one guy standing there holding the actual device notices the power cord is a little loose and pushed it in another 1/8" without mentioning it because everyone is so involved in their nerdy conversation.
Oh man I was going through it in my head too...