this post was submitted on 15 Mar 2025
995 points (99.7% liked)
Microblog Memes
6991 readers
2785 users here now
A place to share screenshots of Microblog posts, whether from Mastodon, tumblr, ~~Twitter~~ X, KBin, Threads or elsewhere.
Created as an evolution of White People Twitter and other tweet-capture subreddits.
Rules:
- Please put at least one word relevant to the post in the post title.
- Be nice.
- No advertising, brand promotion or guerilla marketing.
- Posters are encouraged to link to the toot or tweet etc in the description of posts.
Related communities:
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
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!
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...
Also, welcome to Lemmy!
thanks!
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
If my company fired people for trade show cock-ups we would change the entire staff every couple months. There is a lot of stuff being moved in a short time period, shit is stressfull and you're working at a diminished capacity at least a week aferwards. As long as the stand is not on fire during the show, all is good.
Oh, absolutely. I was just making a bad simpsons reference