70 watts, in a polar vortex storm, with a large heatsink.

@erikziak1249

Жыл бұрын

more likely dipped the test load in liquid nitrogen

@prt1527

Жыл бұрын

The devices are actually measured in extreme conditions by the manufacturer. This is done using a water cooled plate and an excellent thermal contact. Case temperature is monitored and the actual junction temperature is measured through junction forward voltage. This is how the thermal resistance is specified.

@bobert4522

Жыл бұрын

@@prt1527 Likely never was tested like that. It's a cheap Chinese product. Most likely it's just a reference to something from the original design mosfet's datasheet.

@trevorhaddox6884

Жыл бұрын

You could use a refridgeration loop to keep the case well below freezing. But that would only be for a whole bank of transistors, nobody is gonna freeze a single transistor unless it's some weird application where it needs to be frozen anyway (ex, it's running in the circuits inside of an industrial freezer).

@prt1527

Жыл бұрын

​​@@bobert4522 I was talking about the ST replacement part and how power semiconductor datasheet values are determined. Not about the application.

I learn new information with each video of yours. Thank you.

I think your cat is well trained now ;-)

you can adjust settings by holding the button during powerup 😀

Great vid and explanation as alwasy DGW. Thank you! ☺

Always great videos, thank you. ;)

Keep up the good work

Awesome fix and amazing explanations as usual :^)

no schematic?! bloody hell :)

Maybe drill some air circulation holes in the plexiglass over the MFET and Sense Resistors?

That was a easy fix 👍👍👍👍

"Ditch that dodgy chinesium, just make your own!" :) Nice fix.

You should mention SOA...very important. Your videos are great.

I put a larger model display on this unit and it works perfectly.

@chroustek

5 ай бұрын

can you provide link to that model you replaced with?

Very good

BAKED! 🔥

Awww yeahhh. 2 new to watch

Please check the maximum temp. rating at which the LCD display can work reliably....we had experience of some of them fail above approx.(55-58)°C in extented thermal cycling heat run tests.

they do the same thing with switching fets, you can never push the current they say it will take as there is no heatsink that could keep the junction temperature within limits. it's all done to make them look good on the first page. :-)

@davidknightaudio934

10 ай бұрын

no its the max specs at 25c but also affects inrush, peaks, and non repetitive surge currants we need these specs for sizing and headroom we need all the specs to make a proper choice

@TheEmbeddedHobbyist

10 ай бұрын

@@davidknightaudio934 it maybe the spec at 25°C but you try and achieve those currents and maintain the FET at 25°C. it's done to make them stand out as i said. every engineer knows that you have to work with the smallest heatsink that works for your specified performance requirements. but you take the max current figures with a pinch of salt. it might prove me wrong if we look at the RDSon, max current, max junction temperature, and thermal resistance from junction to case at 25°C . would be great to see how hot the junction will get if we pull the max rated current.

@davidknightaudio934

10 ай бұрын

@@TheEmbeddedHobbyist ur not getting what i am saying thats ok i am trying to explain that those figures are very helpful for things like headroom if theres a surge and telling you how it will handle power on inrush and so many other factors we need all the specs the entire data sheet and the rest of the specs are more important than the absolute maximun ratings ofcource

@davidknightaudio934

10 ай бұрын

Particularly the pulsed drain spec and the tj @ 25c power rating

@TheEmbeddedHobbyist

10 ай бұрын

@@davidknightaudio934 All I'm saying is that they use the max ratings in large bold font on the front page, where the non engineers get excited over the part. Where as we understand that these max values all fall over when you start to look and understand the derating curves etc. So in affect they are just eye candy. I once used a 1ohm 1kw resistor which was mounted on a very large with very high powered fan cooled heatsink. As it was needed to disipate over 3kw's with all the loads mounted on it. the resistor blew up at about a 1/4 of its rating, reading the small print it needed a polished mounting surface not just machined to achieve the low thermal resistance it needed!

Great fix, I love video's as this one the most.

I love it good 👍

Maybe I should employ you repairing my larger unit.

So the silicon should have been possibly lightly braised rather than subjecting it to roasting.😏🇬🇧

"When something works partially then you shouldn't poke into it because then it might not work at all." I just tried to fix my multimeter which wouldn't zero perfectly and now I have a multimeter with a broken spring going to the movement.

BAKED.

This is a nice video :) Where do you buy all of your old and vintage resistors, capacitors, potentiometers and all of the other components?

@Mark1024MAK

Жыл бұрын

At least some of them are recovered from other scrap devices.

@abeliever7301

Жыл бұрын

​​@@Mark1024MAKt's not good idea, some of the easyly broke when desoldering

@xxexplosivexxxxexplosivexx8512

Жыл бұрын

He just bought or desoldered them from some old electronics during the old times and kept them to this day.

@Mark1024MAK

Жыл бұрын

@@abeliever7301 - it depends on how good you are at desoldering 🤣

@abeliever7301

Жыл бұрын

@@Mark1024MAK no it's depends on which device to use for desoldering.(Hot air gun/normal soldering iron) . It's not cost effective when it's come to Resistors, capacitor,transistors

Would it be worthwhile to puta huge heatsink on this load so you could do without the fan?

@LucasPereiradaSilva

Жыл бұрын

Why remove the fan? It would make the test load bigger. A fan is such a small load and it only turns on when the heatsink gets hot.

can you make a tutorial explaining Power Factor Correction

Can u post your load schematic on your web page?

I agree with the lesson at 8:53, that's the reason my A/V Receiver has no center channel for speaker output... I do have left, right, and sub though :D Can't complain, something else on it will have to break first.

Does IT has smd mosfets in its pcb??

Baaaked!

Your English pronunciation is like you singing a song, very unusual

@herielrizk

19 күн бұрын

😂

Vďaka tvojej šikovnosti máš teraz dve umelé záťaže (vlastne tri, ak počítam aj tú kedysi tebou vyrobenú), takže paráda. Taktiež pekne vysvetlené zaťaženie tranzistora.

Where are you from?

Did you salvage that knob from a Tesla car? 😁

@DiodeGoneWild

Жыл бұрын

Not that Tesla ;)

Your cat is trained but mine is noob

Ahoj, napsal jsem ti email, rád bych od tebe koupil nějaké GM trubice pokud je ještě máš. Stavím podle tebe mini dozimetr. Díky, Petr.

should I leave the likes at 666 or add one to 667 and get rid of the sign or the devil 🙂

Why not mosfet

@koharaisevo3666

Жыл бұрын

Mosfet in linear region do not work well with the heat.

@blahblahblahblah2933

Жыл бұрын

I agree, it's kind of interesting. I would have guessed a mosfet first too. I made an electronic test load and used a mosfet as well and I'm trying to think if I even considered using a bipolar part.

cat

great video edit: kzread.info/dash/bejne/q5yg1aSGZbrFl9I.html Love it !