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.
nnnNNEEEEEEERRRRRRRRRd!
Right you are. Oops.
If only the oop was here to see this 😔
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.
What are you lookin at
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!
Oh man I was going through it in my head too…
Also, welcome to Lemmy!
I had to think about it too, lol. This is an equation for DC/instantaneous power, and if you want to get into AC math, this is more like a square wave. Averaging the power out over time doesn’t necessarily work with the equation, as you figured out, as it doesn’t when you try to measure AC (sinusoidal) power by average voltage or whatever.
I sure hope someone will be fired for this obvious blunder
there’s the STEM bell curve. XKCD shows the axes as ‘how well your computer works’ vs ‘how well you know computers’. that is accurate.
but if you’ve ever known serious engineers who didn’t just live boring white collar work-home-work-and-some-marvel-shit lives, you’ll have seen things that make this look mild.
edit: and it gets really crazy when you’re talking about a civil engineer. closest thing you’ll ever find to an eldritch location.
Link?
no, sorry; I’m profoundly lazy.
well at least you’re honest
I have my incredibly rare moments. yes.
Should have just left it in, and been able to get the soldering done twice as fast.
New manufacturing hack unlocked: Install 240v outlets at workstations and fire half of the workforce. Golden parachute and douchey, hand-wavey TED Talk, please!
It’s only stupid if it doesn’t work
And vice versa
There are gas powered soldering irons that are essentially lighters with metal around the flame. Real life savers
There are also battery powered soldering irons.
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.
I’ve had mine running off of a power bank before too.
My TS101 doesn’t really work with a phone charger, I use the laptop’s or a power bank
Depends on the charger and or cable. Might not support the right protocol or just be weird when it should work.
yes but that sounds boring and doesn’t require having a functionally super-hot piece right near a reserve of acetylene.
Finally, an usecase for USB irons!
Don’t they have switches?
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.
I think they meant on the wall or outlet not the iron.
Sounds like a cheap portable soldering iron, which just heats up to some roughly usable temperature whenever it’s plugged in.
Textbook definition!
Ive seen some really cheap irons that have zero controls, you plug them in and they operate at max power. Basically a wood burning pencil, really.
An engineer that has a project to show off at a trade show will have will have both a power switch and a temperature control on their soldering iron.
I’m an engineer that’s been in that sort of situation. If it’s planned, you have the tools. Unfortunately, sometimes these things happen and it’s not planned. At that point it’s taken what you can get. A cheap fire stick will still do the job better than no fire stick.
Every one i’ve owned has and I get the cheap ones. I guess you can find them for under a dollar or something
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!
You should have used 200% duty cycle
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.)
There’s an actual commercial product that does this. It even meets UL and CSA standards.
But it wouldn’t be 200%, it would be something like 170% power assuming 3 phases, right. Too lazy to do the math.
You’re correct, but not in North America. We don’t bring three phase to the home.
Our final distribution transformers have a center tap on the secondary coil, bonded to neutral. So, one side of the coil provides a 120v leg with respect to that neutral, and the other side provides an opposing leg, 180° from the first, and 120v with respect to that same neutral. Most of out appliances use leg-to-neutral, 120v. But leg-to-leg is 240v.
(Commercial and industrial facilities can get a wide variety of voltages in single or three phase, and we do have some actual, 2-phase generators and customers: the phases are 90° apart rather than 120° or 180°)
The technology connections video talking about 240v power mentioned some apartment buildings having 208v because they’re bringing in two phases instead of center tapping or whatever. So their comment could be right in the correct locations i think.
I’m clearly no sparky.
Correct. It’s not typical, but it does exist. 208v is usually close enough for 240v appliances.
They are referring to recombining the two halves of split-phase like what is done with an outlet for an electric dryer or oven, but outside the walls.
https://theengineeringmindset.com/120-240v-split-phase-us-can/
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.
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.
Person Wait Modulation.
They need a 1/4 duty cycle.
Hey. If it works, it works.
Any port in a storm right?
Why plug and unplug? Doesn’t the wall outlet have a switch?
Sounds super safe.
