making overdriven components last longer - Page 1
Forum section: electronics / beginners

author: krayvonk
author_rank: Regular Contributor
timestamp: March 29, 2020, 08:51:59 pm
content: Say ive got a 1 watt component, but im putting 100 watts through it.Is there any way I could stop it from overheating - and still have it in the circuit?Or is 1 -> 100 way too much... sorry. i mean if it was a diode or resistor.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 29, 2020, 08:59:15 pm
content: Quote from: krayvonk on March 29, 2020, 08:51:59 pmExtremely cooling it seems your only hope.

author: krayvonk
author_rank: Regular Contributor
timestamp: March 29, 2020, 09:02:53 pm
content: Thanks Mr. Scram.I think ive got a bad idea developing in my head...

author: ogden
author_rank: Super Contributor
timestamp: March 29, 2020, 09:08:33 pm
content: Quote from: krayvonk on March 29, 2020, 08:51:59 pmDo you really think that anything is manufactured with 100x margin? Come on. Be real.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 29, 2020, 09:08:41 pm
content: Yeah, get one that fails shorted.Could you provide any hint ofhow longthese things are supposed to survive?Momentary overload isn't an unusual thing, but getting more than ~ms will depend on having a lot more thermal mass than a typical "1W" component.The easiest watt to dissipate is the watt that you didn't dissipate in the first place: are you sure it can't be avoided through better design (e.g., instead of shunting a surge, disconnect from the source), or greater complexity (e.g., instead of dissipating the power, use a switching circuit to return it to the source, or to a capacitor, or transform it to some other form of energy e.g. EM radiation).A somewhat relevant example of that last case, and quite a pedestrian one actually: lamps used to be so inefficient, you could ignore their light output for heat dissipation purposes. A 100W incandescent might give off 1W of useful output, everything else is useless IR (radiation) or heat (convection). LEDs have always been an improvement over incandescent of course, but even just a decade ago they weren't that much better from a thermal standpoint. They might've dissipated 90-95% of their electrical input as heat. Well, now that white LEDs are over 100 lm/W standard, their optical output is a significant fraction (10-30%) of the electrical input -- this allows chip sizes to shrink, while keeping the same power ratings, or higher!My direct example is a light fixture I built about as long ago, using cheap Chinese "3W" LEDs (~10mm dia. thermal pad with leads style); over time, they aged to a dim purplish output. Not that I could tell how dim they were by eye. Last year I replaced half of them with new, 5050 chip size, brand name LEDs. The new LEDs have somewhat lower voltage drop, much lower heat dissipation, and far more light output. The improvement is immense!Tim

author: Zero999
author_rank: Super Contributor
timestamp: March 29, 2020, 09:40:43 pm
content: Simply put, the energy has to go somewhere and it ends up as heat. There's an upper limit to the temperature the materials a component is made of can tolerate, before they decompose and oxidize giving off magic smoke. The temperature of the component is a function of its size, the power dissipation, the ambient temperature and how quickly it can transfer the heat to the surroundings.

author: atmfjstc
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:28:35 pm
content: Starting to really get a trollish vibe from krayvonk's posts lately.No, you can't put 100W through a 1W component. Pretty sure even if you dunk it in liquid nitrogen, a 1W-sized resistor or diode will still explode.100W resistors are metallic monsters the size of two fingers put together. If they could make them any smaller, they would have done so by now.

author: krayvonk
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:39:28 pm
content: If I get banned, then I was banned off every single electronics site on the internet, just for being honest.

author: ogden
author_rank: Super Contributor
timestamp: March 29, 2020, 11:13:24 pm
content: Quote from: krayvonk on March 29, 2020, 10:39:28 pmYou waste time of other people on purpose anyway. If/when you will be banned here you can blame only yourself and it has nothing to do with honesty. Whats worse - you know it.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 29, 2020, 11:20:47 pm
content: Quote from: krayvonk on March 29, 2020, 10:39:28 pmlooking your track record... i'll give you one piece of advice, if you ignore it, you'll miss it your entire life. you probably will waste your many years and probably others too. it maybe will make you happy in the process, but its just that, happy... my advice is, get a good teacher who can teach you from basic and listen to him, trust him even if you feel like dont want to, just ask him why and proof of real application he should be able to tell you what. if you hate teacher really so much, get a good book in electronics that teach you from resistor, capacitor etc what is volt, current etc, ie basic stuff. try to understand why people keep saying V = IR and P = VI, find out what those are. today's is easy we have internet and you can always ask here in which part of the internet (information) that you dont undertand. the key is read, read, read.. dont just snap things together without getting the grasp of the basic, it can get you killed someday, or wasted time if you are really lucky. either way is bad.

author: Simon
author_rank: Unknown
timestamp: March 30, 2020, 08:21:26 am
content: Quote from: krayvonk on March 29, 2020, 10:39:28 pmOK, humor me. How do you think this could remotely be possible?

author: senso
author_rank: Frequent Contributor
timestamp: March 30, 2020, 11:57:35 am
content: And how do you end with 100Watts in a 1Watt rated device?Post a realistic problem and not some "omg I'm so random"..

author: bd139
author_rank: Super Contributor
timestamp: March 30, 2020, 12:34:48 pm
content: Perhaps he’s designing Christmas tree lights to be sold on eBay

author: Simon
author_rank: Unknown
timestamp: March 30, 2020, 12:36:16 pm
content: Quote from: bd139 on March 30, 2020, 12:34:48 pm

author: AVGresponding
author_rank: Super Contributor
timestamp: March 30, 2020, 12:40:27 pm
content: To be fair, it's surprising how much power you can shove through a small resistor when you have it in a bucket of water, but it's not really a practical solution (sorry (not sorry)) for a working circuit.

author: Simon
author_rank: Unknown
timestamp: March 30, 2020, 12:50:54 pm
content: what confuses me is that yes there are times when you need to push things to their limits but it's for very specific cases with caveats and only when nothing else exists because you have in some way reached the end of what manufacturers guarantee. For example if you were making a tiny device that was to operate in extreme cold and had no room for correct size components then you could say push a resistor harder. Manufacturers normally as standard set full power at up to 70C, clearly they have no interest in testing at all temperatures and getting into warranty debates but if it was so important you could work out how and when you can push it harder. But only when absolutely necessary and 100x overrating is a bit ambitious.

author: bd139
author_rank: Super Contributor
timestamp: March 30, 2020, 01:08:12 pm
content: Indeed. Even stuff in the defence sector is only de-rated 4x or so.Worth reading X chapters on resistors, conveniently a free sample chapter:https://x.artofelectronics.net/wp-content/uploads/2019/11/1xp2_resistors.pdfSection 1x.2.6 on the "Larkin blaster"

author: senso
author_rank: Frequent Contributor
timestamp: March 30, 2020, 03:46:21 pm
content: Quote from: AVGresponding on March 30, 2020, 12:40:27 pmGrab a 1Ohm resistor, try to push 100A at 1V and the leads will melt..This user is just wasting people time

author: TheHolyHorse
author_rank: Regular Contributor
timestamp: March 30, 2020, 04:19:22 pm
content: Quote from: senso on March 30, 2020, 03:46:21 pmGood luck getting 100A at 1V with a 1Ohm load

author: krayvonk
author_rank: Regular Contributor
timestamp: March 30, 2020, 04:24:49 pm
content: what if its a 100 watt resistor.

author: senso
author_rank: Frequent Contributor
timestamp: March 30, 2020, 04:25:15 pm
content: Just break a lead, then it will flow

author: bd139
author_rank: Super Contributor
timestamp: March 30, 2020, 04:33:11 pm
content: Quote from: krayvonk on March 30, 2020, 04:24:49 pmIt'll melt or the leads will fall off. That's usually wattage at 25 oC and it's not going to be running at 25 oC. To push 100A safely you need ~4.2mm diameter conductors for the entire thing not including the resistive element. Go measure the off the shelf ones on the datasheets.A thought exercise. Use extremes to compare. Put 100A through a 0.25W 5% carbon film resistor. It'll blow up if more than 2.5mV are across it if it was a perfectly spherical resistor. But really you have to look at various other things like current density, connections. Those little hair legged resistors will just cease to exist instantly. Poof and they're gone.Edit: Also the art of electronics is doing useful stuff with electronics not just merely contributing to the trash piles we create as a species and the eventual heat death of the universe... although it's fun to just blow shit up occasionally

author: Nusa
author_rank: Super Contributor
timestamp: March 30, 2020, 04:44:14 pm
content: Well, in the earlier days of 3-D printing, the hot end was often heated by a simple 5-watt wirewound resistor potted in a chunk of aluminum. Which was then successfully run at 40 watts or so. But no, a factor of 100 to 1 would be unreasonable.

author: bd139
author_rank: Super Contributor
timestamp: March 30, 2020, 04:45:59 pm
content: Scenes from when that was a good idea

author: krayvonk
author_rank: Regular Contributor
timestamp: March 30, 2020, 04:48:26 pm
content: I bet if you put it in a dc motor it would be more efficient. and generate amazing magnetic fields.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: March 30, 2020, 05:46:01 pm
content: just because you're providing power to a 100W load, it doesn't mean the resistor is dissipating 100W. Do the calcs and determine what you need.

author: krayvonk
author_rank: Regular Contributor
timestamp: March 30, 2020, 08:26:38 pm
content: Need a hydraulics expert.

author: AVGresponding
author_rank: Super Contributor
timestamp: March 30, 2020, 08:41:54 pm
content: Quote from: krayvonk on March 30, 2020, 08:26:38 pm

author: krayvonk
author_rank: Regular Contributor
timestamp: March 30, 2020, 10:04:12 pm
content: That guys have a creamation over his big truck there.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 30, 2020, 10:29:24 pm
content: Quote from: senso on March 30, 2020, 11:57:35 ami think its related to this thread where he tried to implement a super wheatstone bridge as linear dropper controlling motor speed and direction..https://www.eevblog.com/forum/beginners/100watt-400-watt-transistor-to-drive-dc-motor/msg2988810/#msg2988810if you can relate these 2 threads, everything will come to sense again. i think he want to use 1-3 ohm to drop 100W+ and his problem now is economy (budget).

author: krayvonk
author_rank: Regular Contributor
timestamp: March 30, 2020, 10:37:11 pm
content: Ive got a crazy random idea, how about we use voltage doublers instead of transistors!!! =D

author: tggzzz
author_rank: Super Contributor
timestamp: March 30, 2020, 10:40:03 pm
content: Quote from: atmfjstc on March 29, 2020, 10:28:35 pmYes, I agree.I remember the times when trolls posted interesting questionsIt looks like he is on Simon's radar

author: free_electron
author_rank: Super Contributor
timestamp: March 30, 2020, 10:42:06 pm
content: Of course you can do that. Just not for long ...how do you think they make TVS diodes that can handle 600 watt in a piffling SMA package ? 600 watts , for a few microseconds ... check the datasheets.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 30, 2020, 10:51:13 pm
content: no one will ever use linear drop to control motor speed today period, motor has varying impedance vs load, try giving some push to your motor in the other thread, the speed will screwed up tremendously or load profile will be so poor. everybody is using some sort of smps, buck regulation or PWM nowadays. at most in AC world they use capacitor to shift AC phase to make an AC motor run i'm not aware though linear dropper in AC motor, i'm not the expert. as i said, get a teacher or learn from others/internet how to do it. if you just pop out with some idea, you can waste your time alot. good luck! edit: but at least now you know how to make a good water heater, thats a good thing though while trying and error.

author: Manul
author_rank: Super Contributor
timestamp: March 30, 2020, 11:07:54 pm
content: One (and possibly the only) useful thing to be said here is that you can parallel resistors (and usually diodes) to get bigger power rating. There are situations when it can be useful. 10x 1W resistors will have a total power rating of 10W.

author: mikerj
author_rank: Super Contributor
timestamp: March 31, 2020, 08:53:00 am
content: Quote from: krayvonk on March 30, 2020, 10:37:11 pmI've got another crazy random idea: take your childish trolling somewhere else.

author: tggzzz
author_rank: Super Contributor
timestamp: March 31, 2020, 09:13:40 am
content: Quote from: mikerj on March 31, 2020, 08:53:00 amAn example of that is the "connecting to 0 volts" thread he started with"cant u just connect to any piece of metal, and its as good as a 0 volts connection?"Where he is referring to this technique:https://www.eevblog.com/forum/beginners/connecting-to-0-volts/msg2965014/#msg2965014

author: Electro Detective
author_rank: Super Contributor
timestamp: March 31, 2020, 10:24:45 am
content: Quote from: krayvonk on March 29, 2020, 08:51:59 pmYou could wire in series, a ballastand or chain of moist troll accusersthat kicks in at 2 watts and beyond, to save the 1 watt resistor