this post was submitted on 15 Mar 2025
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[–] [email protected] 213 points 1 month ago* (last edited 1 month ago) (5 children)

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.

[–] [email protected] 120 points 1 month ago

nnnNNEEEEEEERRRRRRRRRd!

[–] [email protected] 47 points 1 month ago (1 children)
[–] [email protected] 18 points 1 month ago (2 children)

If only the oop was here to see this 😔

[–] [email protected] 9 points 1 month ago

In my defense, I've been helping a friend with an EVSE install where the load (electric vehicle) is smart. In that context, it's just voltage X current capacity of the line = power. The rest of the story is true as far as I know.

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[–] [email protected] 16 points 1 month ago (2 children)

I sure hope someone will be fired for this obvious blunder

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[–] [email protected] 14 points 1 month ago (3 children)

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.

[–] [email protected] 23 points 1 month ago (1 children)

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.

[–] [email protected] 16 points 1 month ago (2 children)

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!

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[–] [email protected] 7 points 1 month ago (1 children)
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[–] [email protected] 80 points 1 month ago (1 children)

There are gas powered soldering irons that are essentially lighters with metal around the flame. Real life savers

[–] [email protected] 71 points 1 month ago (3 children)

There are also battery powered soldering irons.

[–] [email protected] 40 points 1 month ago* (last edited 1 month ago) (3 children)

I like the pinecil, usb-c powered soldering iron with temperature control. If you are not doing anything intensive any fast smartphone charger will power it.

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[–] [email protected] 63 points 1 month ago (1 children)

It's only stupid if it doesn't work

[–] [email protected] 10 points 1 month ago (2 children)
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[–] [email protected] 56 points 1 month ago (1 children)

Should have just left it in, and been able to get the soldering done twice as fast.

[–] [email protected] 19 points 1 month ago (1 children)

New manufacturing hack unlocked: Install 240v outlets at workstations and fire half of the workforce. Golden parachute and douchey, hand-wavey TED Talk, please!

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[–] [email protected] 26 points 1 month ago (6 children)

Finally, an usecase for USB irons!

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[–] [email protected] 25 points 1 month ago (6 children)
[–] [email protected] 60 points 1 month ago (2 children)

No.

Seriously, many soldering irons don't have a switch. Fancy soldering stations have switches, temperature dials, etc. But basic ones are just a resistive load wired directly to the plug.

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[–] [email protected] 25 points 1 month ago (1 children)

Sounds like a cheap portable soldering iron, which just heats up to some roughly usable temperature whenever it's plugged in.

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[–] [email protected] 20 points 1 month ago

I've had a similar experience as a child. I live in Germany and found this voltage switch on a hair dryer. My thoughts were like: Switching it to less couldn't possibly hurt, could it? Well it could. It was super efficient though but only for a few seconds before it self destructed.

[–] [email protected] 19 points 1 month ago

They need a 1/4 duty cycle.

[–] [email protected] 17 points 1 month ago

Person Wait Modulation.

[–] observantTrapezium 14 points 1 month ago (1 children)

I had the opposite problem, I brought a soldering iron from Europe to Canada, and despite using a step up transformer, it just couldn't get hot enough to melt the solder!

[–] [email protected] 26 points 1 month ago (1 children)

You should have used 200% duty cycle

[–] [email protected] 20 points 1 month ago (10 children)

Splice on a second plug, so you can use two outlets at the same time.

(/s, mostly... this can actually work, if you can find two outlets on opposite phases.)

[–] [email protected] 11 points 1 month ago

Reminds me of the time when I helped install some 120 VAC ceiling fans and the electrician* wired them to the 220 VAC line. They spun like a helicopter trying to take off.

*Worked for the local electric utility, we trusted him, foolishly.

[–] [email protected] 8 points 1 month ago

Hey. If it works, it works.

Any port in a storm right?

[–] [email protected] 7 points 1 month ago (2 children)

Why plug and unplug? Doesn't the wall outlet have a switch?

[–] [email protected] 39 points 1 month ago (1 children)

I have actually never met a wall outlet with a switch.

[–] [email protected] 9 points 1 month ago (3 children)

Really? Where are you for that? I don't have a wall outlet without a switch, and I've never seen one because why would it just be live all the time?

I'm in Australia for reference.

[–] [email protected] 34 points 1 month ago

We're the exception, most places don't have switches on their outlets.

[–] [email protected] 14 points 1 month ago (6 children)

Looks like it's mostly a UK, Australia, and New Zealand thing.

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[–] [email protected] 13 points 1 month ago* (last edited 1 month ago) (3 children)

Germany. It's just live all the time, because why wouldn't it? If you plug something in, you want it to work. If you don't want it to work, you either plug it out (which works just as well as a switch, with the same convenience), OR you use the switch at the appliance because why would you try to reach the hypothetical switch at the wall outlet if the wall outlet is behind a drawer, under a table, or whatever inconvenient place? I use my remote control to turn the TV on or off, I don't physically walk to the wall power outlet.

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[–] [email protected] 8 points 1 month ago (3 children)

Afaik it is a safety thing that is handled differently in different countries.

Uk and their colonised countries have this. The reason is that the fuses are in each plug. But no (or almost no) fuses in the power grid of the house. In Europe most countries have a single GFCI and several fuses for power grid sectors in a single place in the house where the power comes in.

I assume the switches on the power outlets are for turning off a switch because there is no GFCI in the house.

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