Does SMD Size Matter? | Keweisi Ammeter Follow Up
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- Опубліковано 16 січ 2024
- After I repaired my Ammeter by replacing a burnt-out 51 Ohm resistor, I had a number of comments suggesting that the smaller form-factor of the 0603 resistor I used will probably make it fail again...
So, I've ordered up some 1206 ones, the same as the original one in there, and I'm going to swap it out...
Let's see if it makes any difference!
Steve 2 - Навчання та стиль
I'm thinking while the teeny one could clearly handle the current, the fact that the larger one DID fail at some point tells me that there must be spikes occasionally that the resistor...well... resists... And if that happens enough, it will probably weaken the resistor till eventually it can't resist... So the smaller one would probably fail quicker depending on how much you abus... I mean, how often the power spikes... TLDR; replacing it was a good idea :P
Totally agree, thanks Kaltern! Abuse? Me? Never... 🤣
Solid reply, Steve! 🤣
Yea, what they said. Lol
RESISTANCE IS FUTILE
I changed the key fob on my car keys thanks to this guy. Only had to remove 2 buttons, solder on 2 new ones and put in a new case but you have to start somewhere! Saved £70.
Would never have tried before watching these videos.
Failed it's MOT a week later and got scrapped. Stupid car.
I assume you had the equipment to solder circuit boards as well. The equipment isn't worth buying just for that project.
@@Metalborn710 got a kit for about £20. Nothing fancy and I've done a few other odd jobs since.
I've also messed up a few things as well!
Hold up a minute! Your camera "base value" is all over the place. You can see it when you freeze the video right when you pick it up from the blue mat. For the small size resistor, the camera measures about 15°C while on the mat (timestamp 1:29), and 25.6°C on the hot component. For the correct size resistor, the camera already measures about 26°C while on the mat (!!) (timestamp 4:42), and 33°C on the hot component. So I don't think the camera is very reliable for these comparisons. The small component is >10°C temp difference and the new one is 7°C difference so maybe we can conclude that the new one gets less hot.
That music during the resistor replacement was perfect 😊
well i for one am shocked on the results. A big thankyou for the extra work you put into it.
Keep up the good work, your warped sense of humor makes these videos fun to watch, especially when the phrase "Get in there" comes into play at the end of a successful fix, closely followed by "Stupid game/thing".
That resistor is just part of the voltage regulator circuit that provide power to the IC and led displays, would probably have been fine.
The bigger resistor is the one that sees all the current as that is the current shunt resistor.
My guess for the initial failure is sub par parts as these things are made as cheap as posible.
You could go one step further and measure the current draw that flows through the resistor, that would be the best way of testing it.
Just a couple of small pointers to think about:
The power both of these resistors convert to heat is basically the same (R*I²) at the same amp-draw, so the heat in the area would be the same, but concentrated in a fraction of the area resulting in a far higher temperature.
But since the components are rather small the max temp the thermal imaging camera shows is only the average of the area so a local temp spike would hardly be visible, it would only register as a slightly warmer area.
Regarding the higher temp measured the 2nd time the whole board is at least 5 °C warmer than the first run, which is about the same amount the measured heat spot was warmer, so that checks out.
And as always i really enjoyed your videos, it's just so calming and relaxing. And it's just so fascinating how much tech fits in such a small space and how much of it could be fixed, if one had the drive and the tenacity to "get in there".
Thank you for this lovely content you keep providing us!
It's not just the board, the camera shows a way higher temp while it's resting on the mat right before the final measurement. See at 4:42, the camera already shows 25.8°C!
The thing with this guy that makes us all to come back to this channel again and again is not only the electronics, but the incredible chilled out vibe he has, he destroys the stress you might have with his smooth voice, kind temperament, a panda like guy. For sure not married as we all know the hell that leads to. In any case thanks man, your work is way more profound and importat for your audience that what you might actually believe.
No, I'm pretty sure it's VOS. He is the star and future Grammy winner.
@@Boogie_the_catI‘m voting for Dave!
He must’ve borrowed somebody else’s wife and daughter in the other video.
I love the attempt at science, love to see more! I figured you'd go for a load tester, like 1 or 2 amps really stress it out. You still need ceramic tweezers for the surface mount stuff! Can we talk about why your house started at 5c?! Are you rooming with Big Clive??
wow your room must be quite chilly looking at that starting base temperature.... 🥶❄️
Bit like me skimping on replacing electrolytic SMC's, fixed a 32 inch Samsung TV by replacing 4 of the 9 caps under the heat shield on main board. Now got a low tone sound but while it's working you don't notice it. It works and for £3.44 a bargain.
If you look carefully at the temps shown in the thermal camera your baseline ambient temperature is reported wildly different throughout the video. In 1:04 your ambient temp/silicone mat temp is shown as 1C. In 1:41 it has jumped to 11.7C and up to nearly 17C in 4:51. Not sure how much real time passed during the filming and if indeed the room was that cold when you started recording but if not perhaps the accuracy of the thermal camera is suspect. Otherwise kudos for wearing a t-shirt at 1C! 🙂It would also partly explain the temp differences.
Aren't all these values dependent on the reflectivity of the materials? Not sure how a silicone mat should show up but I noticed as well. Given he is wearing a t-hsirt it might not be close to freezing in the room but maybe it is....
When he let the SMD cool down after replacing. It was at 19. Sure it was the room température
If nothing else the solder joints on the new resistor are top! 👍
Really awesome ... knowledge = wasting time
When I was a repair tech in the early 2000s we would sub through hole components for smd all the time. (they were internal device repairs not for customers but they always worked). They were sometimes even better if there were ripped pads involved.
Lol how strange nice theory test thanks Steve 😊
This channel starts to become scientific - nice.
I doubt the resolution of the camera is sufficient enough to actually see which one gets hotter.
Also the current might be a bit low (if the current is low, the thermal energy released gets more time to disperse to the pcb)
The amount of heat (thermal energy) created is of course the same, as the resistance is the same. A smaller component however has less surface area to dissipate that heat, and therefore it would get hotter. But to see that, a bigger load on the usb port would be helpful.
For experiments like this, it's therefore also better to use an electronic load. These are more controllable too.
The endresult made me chuckle
My guess is volume to surface ratio wise the smaller has less heat accumulation / dissipates heat faster. Heatsinks also increase the surface.
As long as the resistor is SOLID. The original one very much was not.
The resistor is not getting hot by its size. The temperature is related to the power that is running through it. Let's say it was 100 mW, then the small 0603 willl.not be able to dissipate that power and burn. The bigger one yes, since it is rated for 1/4W (250mW)
The total temperature should not really change when you use a same value resistor however the surface size change making the camera pick up that spot better probably making it read hotter. the larger resistor should be able to handle higher current before it burns than the small one but the dissipated heat will be the same but on a much bigger area
Another fun and informative video as usual, would be interesting to see what heat it would get up too with a higher amperage draw through it, I suspect with higher amperage the larger form factor resistor will dissipate the heat better 🤷♂
Also no song in this video.. kinda disappointed.
True, that thermal cam was only drawing roughly half an amp.
No singing, thats perfect !
To short of video, I'm sure the cringe will continue on the next video
You're like the Benny hill of electronics repair. Nice.
As you move up in physical size the wattage rating also goes up. 1206 is about 1/4 watt. If it gives you any trouble get you a through hole resistor rated for 1 or 2 watts. That should handle the heat. 😊
You can buy 1206's rated for 25mW up to 16W. At least.
@@grantm902 Wow, all the ones I buy are basically around 1/4 watt. It almost doesn't seem possible that a 1206 could be 16w. Where do you get these crazy high wattage ones?
That shirt is very rad
In a pinch, if you have enough room on the pcb, you could use two resistors of double the required resistance and mount them in parallel which will halve the resistance but double the current handling capacity. Ex, two 100 ohm quarter watt resistors in parallel will give you one 50 ohm resistor at half watt. You can do the same with capacitors except with capacitors you will double the capacitance value. Now I suspect you already know all this but, just my 2 pennies.
Resistors by design will get hot. You can get 0603, 0805, 1206, etc in different wattage ratings. Of course larger package sizes can handle more volts/current by design, but it all comes down to what they do in circuit. Resistors can be put in circuit to act like fuses, so wattage can be important in circuit design vs general use because hey are intended to burn up not keep truckin when things get out of hand. (Resistance value is still important, but the wattage determines how fast the resistor will last before it fails to protect the circuit it is in)
In the event of shunt resistors for current monitoring, the internal resistance must be very low by design and handle some wattage with low drift due to temperature to ensure accurate results.
Nice
The 0603 smd resistor was rated 1/10 W (100mW) and is just for the power of the electronics via the regulator(smd like transistor) I don't think it draw more than 100 mW. You could let it. The measurements are done using the other big resistor.
That was hilarious. Keep up the good work. Or something.
It's not just temperature - it's DIFFERENCE in temperature. When you measured aboiut 25C, the background was reading about 11C (ie. 14C difference).
On a smmer day in Australia, background temps of 35C are not uncommon - which would put that resistor at 46C.
BEFORE you consider spikes and surges.
Do more comparisons. And explain the difference or why or uses. For example....types of solder.
Higher resistance would be hotter though. The power draw on the other side is consistent. So watts = current squared times resistance. If current is constant and it is in this case but resistance has increased then so too has power........and in relation to that, the amount of heat will increase.
Just an observation, but I was told to always have a clean Soldering Iron. Pleas don't shoot me. As I said, just an observation. Love you Vids.
Nice vid, as always. Thanks.
Just want to ask if its ok to mention. Where do you get all your parts from ?
I used to own the exact same USB meter. I didn't find it such a reliable way to do the measuring, the readings aren't that accurate, the resistance of the contacts is also another problem it, dropping considerable voltage. Perhaps you should test the accuracy of yours.
As the old saying goes, if it ain't broke, don't fix it 😂
anyone who said that never knew how to fix it to begin with, preventative maintenance is a thing.
Apologies if I'm stating the obvious but the heat would likely relate to the current being drawn, bigger current, more heat.
Did this get taken down? Went to watch it and it wasn’t on the channel and has now re appeared
One would think the physical size would make a difference and I am sure it does. Because I think the size changes per wattage rating. So the smaller size probably can't handle as much wattage as the larger one... But what would I know?
You could have just measured the voltage drop across the resistor and then calculated the current and power dissipation to check if the ?0603 part was adequate.
"Some" resistors. Blimey 😆
What was the wattage rating for the resisters?
You only tested it open air. Inside its housing it will go thermonuclear.
while a thermal camera is great for finding heat on a circuit board maybe a thermacouple would have produced a more accurate result.
Size is not the end all be all, the smaller one may have a higher resistor rating.
It's not all about the size ;) You can get 250mw 0603s and you can get 250mw 1206s, yes the 1206 will be able to dissipate more heat and will run cooler. If this is in a 5v circuit you should replace it with a 500mw resistor, unless you can ascertain the maximum dissipation is otherwise.
It's not the length, but the girth of the resistor that makes the difference. -Cookie Monster's mom
Wasted 5 minutes of my life. Well worth it. Feeling better Perhaps I will return those puppies.
…who put the Shunt in Shunthorpe? 🤔
Ohm my. Not knowing enough about the actual physics, I'm hopeful that what you're seeing is a larger surface area being able to dissipate heat more quickly. But in something that small I dunno. It'd be interesting to hook some of them up to a bench supply and verify current in/out. Mathematically it all has to work out, right? So anything not becoming heat is getting passed through.
Music from COCKTAIL (the film)? :)
The smaller one has less thermal mass so your massive solder blobs will sink more heat from it. IT may not hold up as well to actual strain though. That's my hypothesis.
Similar to my experience of LG products, any repair of this Keweisi product will be better than the original.
Emissivity did you a number there... with the tiny resistor, the ratio of shiny solder to slightly duller component was much higher, so it read cooler on the thermal camera*, due to its resolution. For more accurate readings, use a better camera and put some black electrical tape on the object under test or, better still, paint it matt black.
Try filming the wetted tip of your soldering iron (so with a shiny coating of fresh solder on it, because you know what temperature that is at to within a couple degrees) with the thermal camera to get a feel for the kind of error emissivity can introduce.
As an electronic engineer (my original major) I can assure you a 1206 surface mount resistor will run cooler and last longer than an 0605 (was it?) one of the same value, in the same circuit.
As a, now, meterology engineer, I can assure you an affordable thermal camera will never produce a practically accurate reading of "a temperature". Differential readings (area A is hotter than area B) can be quite accurate, though.
(*): your baseline is way off on that as well; no way are you sitting in a room that's necessarily as cold as the objects in it (room temperature, 16 degrees centigrade according to the thermal camera) in a T-shirt. I'm currently sitting in a room that's actually 16.2 centigrade (give or take 0,05 degrees**) and am wearing a winter track suit with a sweater over it.
(**): and, yes, I do have an accurate, calibrated thermometer. I work for an ISO17025 calibration/certification company. We have a triple point reference. Under ideal conditions an uncertainty of 0.0001 degrees can be acchieved with one of those, but, to be on the safe side, we claim 0.01 for the "arm and a leg" thermometers (which take forever to settle) and 0.015 for the one I've got.
Where do you buy these?
You still using RMA-218 flux...... and if so, do you recommend it?
Who does your music?
😊add thermal pad.
Mount two 100 ohm resistors in parallel.
your room seems to be very cold if the rest of your tester is way lower than 24°C :)
"Stupid resistor." :)
no flux again...
Awesome. Or is it?
Just put an aluminium power resistor on there. That will handle the heat. 😁
I missed your music
1:05 did u really have -1.6 C on the mat ?
im confused. Who won?
THE ORIGINAL RESISTOR.
I mean probably doesn't matter much but you did plug it into different ports each time. 😅 otherwise Get in .. 😂
me here wondering why you lost 90 thousand subs....took me a while
Where is all the new content Steve I miss your Rapping/singing. On a serious note hope all is OK?
Stupid chip 😅😅😅 getting even more 🔥
4:54 makes sense the resistor with the higher value is gonna get hotter. Pushing the same current through it the higher value is gonna shed the higher resistance as heat.
Actually the reverse is true. The higher the resistance, the cooler it will run as it is passing less current. Imagine how hot it would be with just a wire across it (ie zero resistance - sort circuit) and then think about leaving it open (infinite resistance). The first gets really hot, the second not hot at all. The fact that the package it comes in is larger doesn't affect it.
@@pintokitkat no, pushing the same value of current the resistor with the higher value will be hotter. By your logic a zero ohm resistor would be white hot.
CAN YOU DECIDE PLEASE???@@patrickradcliffe3837
The resistor produces heat exchange for reduced volts and amps. The higher resistor will get hotter. As it’s reducing more.
Buen arreglo, yo si no tengo resistencias smd hago uso de resistencias comunes 😂.
Mouser stocks some 0805 resistors with a power rating of 20mW and some with a rating of 3W. Size is just a very, very, very rough indicator of what the rating MIGHT be.
Stupid higher temperature
Would be funny if you just took out a perfectly good resistor and fit a faulty low resistance one causing the excess heat. Did you measure it before fitting? lol
I'm not convinced that the last resistor burned out. It's sitting directly under an USB port. Close proximity to ports that get plugged and unplugged is not ideal for SMC on thin PCBs. The PCB flexes every time mechanical force is applied to the connector, and sooner or later a solder joint or the SMC itself fatigues and gives way.
Larger surface area = higher heat dissipation. The heat camera is probably adding up the temperature derived from the red pixels altogether. Use another thermometer to confirm.
hey steve i got the same usb doctor and where you replaced your resister, mine say 680. i can send you a image of mine if you like, let me know
It's larger, thus it's dissipating MORE heat. The smaller one would become defective if it was unable to dissipate enough heat through it's tiny body.
How it is possible you have only 5 degree celcius on the desk? Are you using table to make ice cream or what? Just friendly reminder that water freezee at 0 degrees celcius and boil at 100, human body is 36,6. I think you should recalibrate your thermal camera or move inside
I dunno ask your wife😂
The larger value resistor is dropping more voltage than the lower value one therefore more heat is generated.
So many electronic experts here watching an amateur repair channel. Gosh.
Of course the larger resistor is hotter it is designed to dissipate more power than the smaller one, its a resistor ffs! Thats how it gets rid of the power as heat 😂
Not very scientific. The discussion, testing methodology and analysis is poor, to put it mildly.