Test of the Yihua 502D USB bench power supply. (With fix!)

[@MrFmiller]

I like the retro 50's look of it. The size is actually very practical. The room inside with vents help to minimize components from overheating and the large meter is pleasing. In this day and age of miniaturization to the point of marginal safety and utilty it's nice to see something that would not get lost beneath a postage stamp. A little judicious tweaking makes it perfectly functional. A bit of QC at the sweatshop would have been preferable but otherwisw I'd give it a crooked thumbs up.

[@fun_ghoul]

The nineties are the new fifties?

[@petehiggins33]

I see that flash tester has a "BURN" setting, I'm surprised we haven't seen that in action.

[@neville3151]

I envy your ability to draw an accurate schematic from just looking at a printed circuit board.

[@stonent]

It looks like a late 1990s computer speaker case.

[@Florian00]

stonent I thought it looked familiar lol

[@HDXFH]

A clone of one

[@Sopheris]

Maybe it is. They just put ammeter in place of speaker :D

[@eyeswideshut7732]

sound blaster 16

[@John_Ridley]

CE means Caveat Emptor :)

[@woldemunster9244]

China Export, that means you MUST export it out of China or be sentenced to death by firing squad. :D

[@GaffaTV]

And I'd always thought it was "could explode". Pity. :P

[@alexanderthomas2660]

“Crap Expected”

[@jammin023]

Clive Eviscerates.

[@fun_ghoul]

Conceived by Europeans?

[@SkyNines]

Still waiting for the day that little fan kicks on.

[@bigclivedotcom]

It does on long high current tests.

[@colinkraus7139]

This comment! Yup. This one.

[@gameshark528]

Have seen it spin in 1 video, wished I remembered which one!

[@ovalwingnut]

A "classic" from 2018. Very COoL. Thank you.

[@Lada_Niva]

I love your reviews, you continuously consider our mere mortals, and manufacturers, and therefore obviously install trust in your very educational videos - we can see and understand what you do (and what the designers/manufacturers intended)!!! Please keep up the exceptional work!!!

[@Mark1024MAK]

Yihua 502D USB bench power supply 5V 2A PSU Clive used 47k ohm I went with a 56k ohm 1% This gives: 5.21V with no load, ripple 4.4mV, 5.12V at 1A, ripple 63mV, 5.05V at 2A, ripple 84mV. I then added 470uF 16V and 100nF ceramic capacitors in parallel on the front panel PCB connecting these extra capacitors across the PCB tracks near the output terminals. This lowered the ripple voltage, now I get: 5.21V with no load, ripple 1.8mV, 5.12V at 1A, ripple 22mV, 5.05V at 2A, ripple 31mV. Mark

[@xKatjaxPurrsx]

Seems like a nice case... just awaiting the transplant of a better power supply circuit.

[@channelsixtysix066]

"I Think I'll Give This The Thumbs Down ..... " - Right, well that's it then, innit. 14:55 "I'm Not Giving Up That Easily .... " - And another bit. I'm glad you were able to rehabilitate this supply. It did seem to be worth the effort.

[@paulstaf]

The "Muppet" song came from an Italian soft porn film. www.slate.com/articles/arts/culturebox/2011/11/_mahna_mahna_how_a_ditty_from_a_soft_core_italian_movie_became_the_muppets_catchiest_tune_.html

[@bigclivedotcom]

Excellent. That makes it even better.

[@rootlessmisanthrope2611]

bigclivedotcom I actually saw it at the cinema when I was 16 or 17. Very disappointing I'm sorry to say.

[@Mark1024MAK]

The things you learn on this channel 😳

[@raymondj8768]

mark i know its fkn crazy isent it hahaha

[@BPantherPink]

N-I-C-E... Thanks for scouring this link !!! Cute girls too !!

[@CoffeeFurret]

Even though I don't understand anything about electrical work, I find Clive's voice soothing. Plus he takes shit apart and I like that.

[@bryandraughn9830]

You are quite forgiving when it comes to the intentions of the manufacturing. Great video!

[@chrispotts2010]

Oddly enough, I had the "muh-na-muh-na" Muppet song in my head for weeks. Just got rid of it when YOU set it off again!!....bugger!

[@tncorgi92]

Chris Potts same here. I somehow picked it up last Friday. It was gone til 20 minutes ago.

[@Tore_Lund]

Both of you and Clive got it wrong it is not "bananamam" or "Mu-na-mu-na, it is "Manamanam": kzbin.info/www/bejne/q36xoHichrJrgq8

[@Mentorcase]

I use the tune when someone says the word "phenomenon".

[@Milamberinx]

The fact that Clive said it as bananana made me think of the banana phone song. Ring ring ring ring ring ring ring bananaphone do do du dodo

[@hendrih.5349]

This is cool, I am glad we have guys like you on this platform who give so much information. Keep up the good work!

[@corum10]

I love this little PSU. I give it a big thumbs up. I added a Pot to con3 like you did and tweaked it good. I however wasn't surprised by the lower than 5V because on the ebay listing I got it from it said: Output Voltage: 5V -6% (that's 4.7V). Still unsure as to why they did that though. Anyway, I put it under load with 2A and zero resistance and tweaked it to 5V. Now without load it's reading 5.21V. What I'm doing now calls on another BCDC thing...I've installed 3 nokia Lithium batteries and hooked my 12V solar panel to it. Switch between power sources. Love this little box.

[@picsi-software]

bet the 1A is the rating of the supply fuse :)

[@Biffo1262]

I agree as the vendors do state it is rated 2 amp.

[@_Jamie_]

I thought CE meant Cheap Electronic!

[@Manorainjan]

CE means China Export

[@kruemmelbande5078]

Cheap electronics Could explode China export Where is the difference? There is none..

[@gordanmilne7034]

Crap enclosed?

[@saddle1940]

Replace the 5v board with the one from your switched power socket.It seemed to be a better design (and you were very impressed with it.

[@JonathanWinterflood]

Clive, I suspect the 3mA on the Opto LED might not be enough to drive the phototransistor into saturation, causing significant dissipation in it. Or maybe the IR from the LED leaking and messing with the FLIR ? try taping a bit of AL-foil to the opto to block IR w/ some black tape on top and FLIR it again to see if it's really that hot?

[@Chuckiele]

3:48 "But I dont have banana to banana" That actually surprises me :D

[@HighestRank]

Chuckiele I see what you did, there. So does everybody else, I suppose.

[@gameshark528]

That's why you use hotdogs.

[@hrnekbezucha]

And to avoid using the death-dapter you'd have to replace the lead. It might be nice to replace the insides with a decent phone charger and make a Frankenstein's monster power supply with a neat readout. Depends on the amount of hassle and price of the unit Edit: it's about $20. With that in mind it's suddenly a much tougher sell.

[@RossMitchellsProfile]

Or you could just cut the end off and replace the plug with a UK plug that you can often find for less than £1 in stores.

[@MarsyTea]

I rarely tinker with electronics but I really enjoy watching these videos

[@HighestRank]

Cake Mix get baked or get back into the box.

[@alanr585]

Yeah, that's the sort of wire stripper I've always liked because the action seems nicer to me and more controlled than the common labeled entry type.

[@Ragnvald49]

Proper telephone engineers end stripper I use nothing else.

[@Nono-hk3is]

Do doo, duh doo doo, duh doo doo, duh doo doo doo duh doo........ Bananana...

[@doormattde]

I wonder how many people don't get the reference 😂 Manamana dodoo do do

[@mathuetax]

Astoundingly few, though to be fair it is a pop reference.

[@TheAlphaWolf2013]

Thanks Clive. I won't be able to get to sleep tonight with that tune going round in my head.

[@SianaGearz]

It's OK, you can use the long back catalogue of Clive videos to lull yourself to sleep. Well, unless you don't fall asleep till you get to Big Fish Little Fish, or the Shitty Pink Charger from China song.

[@1blisslife]

Matthew Hawes Clive make it stop!!!! Btw thanks for the spoiler alert Matt.

[@heyarno]

It's just lovely that the warranty seal on the insulation tester is already broken :D

[@jlucasound]

"It's tolerable". And it's cute as hell! :-) I love the analog meters. (Yes; I'm Old!) I am glad you were able to tweak it.

[@em0_tion]

It's either old-school, heavy, metal & glass, maybe with USSR markings or LCD screen for me. These Chinese plastic cheapos make my childhood memories scream in disgust 😂

[@bobsage4963]

Same here - nothing screams "TOO MUCH!" like the needle wrapping itself around the end-stop. An LCD flashing "OL" just doesn't carry the same emotional impact... 😁

[@mattmoreira210]

4:50 it's called "hiccup mode", and is a short-circuit protection mechanism.

[@zh84]

How accurate is the ammeter on the front panel?

[@bigclivedotcom]

It seems pretty accurate.

[@t4teeee697]

bigclivedotcom it's nice just for that

[@HighestRank]

You won't be crystallizing any Germanium with it for the Japanese. It's not a mirrored scale.

[@user-yw8sr3uj1w]

@@HighestRank tf?

[@JerryEricsson]

Well here it is, 2021, the world has changed, the age old question "who was that masked man" has taken on a much different meaning. Following this video, I purchased that power supply, added that resistor and it has been my primary 5 volt power supply when I just have to have over 1.2 amps power. It does a wonderful job, runs all my little single board computer for testing and setup with operating system, it has never given me an ounce of trouble even though I have a set of LED'S hooked up to the screw terminals to light up the shelf where it lives. When ever I need the light, or need the power 5 old LEDs mounted on a strip recovered from an old LED flat screen TV that ended it's life when the damn cats started fighting behind it and actually knocked the blasted thing on the floor shattering the screen. At least the led's are serving some purpose. Cats still run the damn house too, the penalty I have for inviting my daughter to come live with me following the death of my lovely wife of 51 years. She cooks and cleans for me, and insures I don't go off the deep end so I guess the cats are worth it, plus the cats have long since settled down and become my friends and nightly companions sleeping in the bed to keep me a bit warmer in the cold Dakota nights.

[@shmuck66]

remember it is an IR camera :) what led do you think is driving that opto-isolator? :) seen this before where IR leaks out of the opto isolator package making it appear hot to the thermal camera

[@raykent3211]

Nate Terrs fascinating, I didn't think of that. It would be interesting to drive a naked ir photodiode and see the response of thermal imaging compared to a trad thermometer. As you know, ir radiative intensity is not the same as temperature.

[@jan.tichavsky]

Remember that IR camera captures much longer wavelengths than IR LEDs (which are near visible range). It has to be because the thermal camera is detecting black body radiation corresponding to relatively low temperatures where the wavelength is out of range of usual CMOS sensors. IR LED wavelength is close to red hot glowing material. Also have the optoisolator package transparent, or at least leaking, infrared light would defeat the purpose of accurately transmitting light based on applied current. What you see on the picture is actual surface temperature of the package and the small current going through the LED won't heat it up.

[@shmuck66]

Well Sir, how do you explain the fact that every time I am imaging an opto isolator I get these same crazy results, which cannot be replicated with a thermocouple attached to the surface of the opto isolator? I would be happy to see a proper explanation. Until then this is what I am going to believe, because there is no way the thing is 60-100c and my finger or thermocouple is not feeling it.

[@lwilton]

You may have a good explanation here. According to the data sheet, the current into that control pin should be 4ma. While it varies with duty cycle, it varies over the 6-2ma range. So with 3ma into the LED, the package worst case should be sinking 9ma. The control voltage is nominally 5.7V, and if we assume the feedback supply is roughly 12V and the LED fires at arodun 2V, the package should be dissipating 2V * 3ma + 6V * 4ma = 30mw, which ain't much.

[@chasmosaurus3]

We could test this. Point an IR remote at your FLIR camera and see what it reads.

[@JerryEricsson]

Well I had to watch this one once again.. WHY? Well I tired of the political fight that we in the USA are now engaged, following the bloody Saturday that ended last week with so many dead or wounded. Nice to relax to the sound of Big Clive, and talking about my favorite 5 Volt Power supply. Having used it now on at least a weekly basis, I can testify that she is a great little power box! I love the needle for a quick view of the amp draw, never though about how nice that would be till I have it. I have a set of crock clips plugged into her all the time, they hang from my fan remote that is attached to the side of my old desktop PC desk that now serves as a sort of work shelf next to my old electric recliner where I spend my days trying to count out the hours upon hours that I still have in this wicked world. Over the past couple of months I have built several rather good variable power supplies, some with fixed output banana plugs, others with variable voltage and one nice little unit with both amp and volt variable, yet when it comes to 5 volts, I always reach for this little guy. Could be because it rests right at my elbow while I have to plug in the other, or may be not.

[@nickbolhuis7467]

Thanks Clive :) I find your hacks, & repairs more interesting than your more common power supply circuit traces and look forward to more content like this. Have you ever tried keyboard bending?

[@tomvleeuwen]

It seems to me that the 1A rating on the back refers to the primary side fuse.

[@bigclivedotcom]

It does. I updated the description.

[@HighestRank]

Tom comó Sè debería.

[@ReedSwitchTube]

I think it was a low power power-supply.

[@erikandreassen6531]

Interesting the back label says it's rated at 1 amp but then the spec for the usb port is 2 amp. After watching this I'd say the 1 amp label would be the safer option to go by. Thanks for the fix because the unit looks interesting.

[@bigclivedotcom]

It appears the 1A may relate to the fuse. It does appear to be rated 2A.

[@ElmerFuddGun]

Back panel current specs always refer to input current. It is right below the input voltage. That is standard in North America and I thought the world. It is there so you can judge what and how many devices can be used in an AC circuit safely. If it was referring to the output it would say so along with the output voltages _in addition to_ the input specs.

[@HighestRank]

ElmerFuddGun don't let Fudd fool ya. We Americans all write in rows from left to right, and things in columns don't have any relation except to indicate graphical parameters for a given range. Top to bottom is how to wash cars, not how to read latin letters.

[@Demiglitch]

Seems like an interesting little device regardless of what you had to do to it.

[@imqqmi]

OHH BANANA!!! Would also be interesting to see how much noise these psus produce versus load using an oscilloscope. Keep up the good stuff! Cheers!

[@LiamCotterz96]

Could you teardown a lightning splitter for the newer iPhones? I’d love to know how they work

[@twotone3070]

I'm pleased to see you were paying attention during your Latin classes.

[@bigclivedotcom]

My dad was a librarian who spoke a lot of Latin.

[@Space_Debris]

3:46 When was the first time hearing that melody? Late summer 1967±? on The Red Skelton Show during a _Moon Man skit._

[@Boffin55]

Probably a nice solid 5.1v before the output diode. Replace it with a Schottkey, and it would be fine.

[@mjouwbuis]

The feedback is after the diode. Mounting a Schottky if not already fitted, would drop the temperature a bit, though.

[@HighestRank]

mjouwbuis I did not realize that temperature of a feedback is controlled, measured and utilized. That amazes me. What is the target domain and its units, if I might ask?

[@bskull3232]

The diode is a schottky, otherwise it would blow up at switching frequency. The high internal resistance, I guess, comes from the amp meter.

[@PsiQ]

the ampmeter is after the complete circuit, so there is another voltage drop. I bet you could find a point before/in feedback to improve load drop.

[@bskull3232]

And the inductance may screw up the feedback loop.

[@tristan6509]

This is pretty usefull for repairing phones, you can tell if there's a short on the charging circuit or fault in the CPU by seeing the amperage

[@garethwilliams3819]

I wonder if the delux model had a pot to adjust the O/P voltage

[@gordonlawrence4749]

I think that the voltage being set to approx. 4.6V is a symptom of the feedback issue. IE set the voltage to 4.6V and the voltage on the output of the feedback winding will be approx. 10% lower than if the output was set to 5V. V=IR so P=IIR and reducing current by 10% (assuming the feedback in the chip is a resistive input which they usually are) will reduce the power dissipation by 19% approx. Set the output voltage to 5V and things will get really hot.

[@Slikx666]

Hi Clive. I used to work in Argos 0475, restocking the shelves. One Christmas I made a CD which had 26 tracks on it, unfortunately it was only the Muppet music. The stockroom manager kept playing it over and over until the Muppets (staff) did something useful. I'm just glad I worked nights, but we still played it for over 6 hours Mon stop.

[@capatainnemo]

the muppet tune gets triggered in my brainbox when i hear the word phenomenon

[@Mountain-Man-3000]

captainnemo Thanks a lot. You've just ruined the word "phenomenon" for me.

[@kraio-sfu]

Phenomena DODOOOOOOO DODODO

[@Darieee]

The flir printouts look top notch !

[@HighestRank]

Darieee unfortunately they're also misleading.

[@Darieee]

how so ?

[@benhobby17]

15:01 "I connected a couple of connections to this connector" impressive

[@Nono-hk3is]

Where does the coupling occur? I thought the transformer would provide isolation. Edit: oh through the control pin of the chip?

[@bigclivedotcom]

Leakage comes through capacitive coupling between windings and the class-Y suppression capacitor.

[@HighestRank]

No no Yes yes when you put capacitor and coil in parallel, it results in resistance, not a band pass filter where the connection would be in series.

[@bobbailey8246]

Hhmmm! Fused neutral on a cable with a two pin plug that can be inserted either way round. Better than no fuse at all I suppose.

[@MadMorgie6318]

Lucky for me, Clive, I _like_ that song!

[@ian-c.01]

There are some similarities between that circuit board and the USB power circuit from the British General USB wall socket in the previous video. The other one is smaller but I would think it would be a better option if it could be mounted inside the box.

[@chrisreynolds6331]

I've had lots of issues with the floating AC aspect of USB power units. I have some power strips with USB and there's always that 90 volts AC to ground at a few microamps. I found when I was charging my phone the touchscreen was erratic. Not surprised really. So I have reversed engineered them all. Dismantled and soldered a wire from the USB socket housing to the mains earth bar of the power strip and had no more problems since.

[@YodaWhat]

@Clive - With the panel meter going to 2 A full scale, I would have interpreted "rated current: 1 A" as the *maximum inrush* current _at 220 volts._ I was surprised you did not measure Power Factor, which might have some bearing on maximum inrush current from Mains.

[@jamesvalentine925]

I got an Aneng AN8008 multimeter a while back as I wanted a cheap second meter, I chose that one as it comes with a big bundle of lead ends including banana to banana, screw terminals etc... They seem to get reasonably good reviews from the likes of EEVBlog considering the price.

[@clynesnowtail1257]

Wonder if you could modify it to have the vsense somewhere on the front panel board. That ammeter is probably indroducing a decent amount of resistance at high load like 2 amp which is why even with 5.25V@0A it was still down under 5V just before cutoff. Would be easy to check though; see what the vltage is at the board before it goes over through the ammeter to the front panel.

[@BensSightSoundandAuto]

The 1A rating on the back appears to be for the fuse after buying one of these for myself. The mains fuse is 1A, you will note the fuse symbol adjacent to "RATED CURRENT 1A" on the label. The fuse is a fast blow 1A. The supply easily delivers 2A output

[@rich1051414]

That voltage drop isn't bad at all. Fixing the 5v reference would make this thing quite useful :P (5.1v with no load would be ideal, imo)

[@JerryEricsson]

Makes one wonder; could that connection be for an upgraded unit with a variable resistor so you could set the voltage, perhaps with a second meter to show the voltage out? Makes perfectly good sense to me, perhaps install a variable resistor and one of those sweet little digital volt meter that china sells for a buck two fifty?

[@rbmwiv]

I have had many cars in the shop with the digital displays having a wave or pulse. Go check the alternator and it’s putting out some AC voltage. The bridge rectifier is going bad and time for a replacement alternator. Usually it’s been to other places and they couldn’t figure out what was wrong. So anytime I see a display do that I see if it’s putting out AC.

[@__-nd4hf]

Oh, that volt count ONE THOUSAND VOLTS FIFTEEN HUNDRED VOLTS TWO THOUSAND VOLTS I miss PhotonicInduction videos so much. YOU MADE ME REMEMBER IT AGAIN, CLIVE!

[@restcure]

I'm disappointed that he didn't crank it up to the 4kV range and make a go at it.

[@__-nd4hf]

I expected it to let some smoke out, especially from that control chip

[@FennecTECH]

So much hardware that they actually tried to make it safe!

[@HighestRank]

FennecTECH they knew somebody would open it and fix it, so r&d made it cost more.

[@hadireg]

Addictive channel 😊🙏 Thanks Clive!

[@khronscave]

Between the dedicated chip from Power Integrations on one hand, and the opto-feedback on the other hand, that looks indeed like a half-decent little unit. As opposed to, say, some bottom-of-the-barrel two-transistor oscillator with aux-winding feedback... Maybe with an electrolytic "critical cap", which upon failure, makes the secondary voltage go sky-high...

[@VerstehenSieMathis]

Looks like the optocoupler is not turned on/off fast enough, because zener diode's characteristic curves are not really "rectangular". So the transistor spends too much time being "half on" and thats when it gets hot.

[@amorphuc]

Too bad you can't double like stuff. Very interesting to watch some of these a few times. Thank you.

[@Zadster]

A friend of mine recently worked in Manama for a time. Yes, Manama. No, my brain wouldn't stop doing it either!

[@233kosta]

Rated 1A at 240VRMS, no? Should the 2A 5VDC output not require significantly less current from the mains? I'd have thought on the order of a few hundred mA?

[@andrewwhite1793]

Maybe the on-load drop is the panel meter. Some cheap current meters have quite high series resistance.

[@bigclivedotcom]

I did consider that. I may have to revisit this little power supply again in the future.

[@jcudejko]

3:40 didn't expect this man to start singing - but there you go

[@akkudakkupl]

I'm tempted to buy this Yeeeeehaw! PSU for digital projects, should be adequate for simple stuff.

[@233kosta]

I'd say a worthwhile endeavour would be probing various bits & bobs on these circuits with a good old fashioned oscilloscope. The switching on that optoisolator for example ought to show up rather nicely. That and output ripple, though I don't know how much modern day electronics care about input power ripple - you're in a better position to make that judgement. Also it would allow for some interesting comparisons between "proper" OEM power adaptors and the poundland specials (especially the good ones!)... I mean they *say* it's DC, but... That said, there's only so much the scope can pick up, so some sneaky really high frequency switching noise might make it through undetected :/

[@pojcharapoltosukowong]

I got one of these unit awhile back, and found that the output seems to be live at half the mains voltage. (Thailand uses 220V@50Hz) So I just took out the power supply board and replace it with DC buck regulator, so I can power it off an "known good" DC supply. Since then, its very useful for testing cables and 5V powered devices

[@bigclivedotcom]

A typical multimeter will show that due to the filter capacitors. It's usually just at around 100uA.

[@pojcharapoltosukowong]

Maybe it’s some defects in my unit, I got an electric shock when touch one of the terminals. Being suspicious I measured the output terminals with the (isolated) handheld oscilloscope and found out the 5 Volts sides has around 95-110V AC coupled to it. I also tested it with the mains tester and it seems to confirmed the same thing.

[@felenov]

The power supply module inside is a pretty standard part and it is double insulated

[@englishrupe01]

Interesting video. How much is it over there? It's $60 here in the USA on Amazon! I was expecting it to be really cheap. I guess $15 on Banggood is the way to go, then. P.S Our E Bay listing here states that the USB socket is 2-amp but i doubt it's any different in fact than that one. This one is offered at $23.

[@160rpm]

Is this a standard use for an opto-isolator? I thought they wouldn't be able to pass a load like this, or is it just the LED part that would be more sensitive to overloading?

[@yuriismywaifu203]

That's a very stylish power supply. It'd be neat if you could make an adjustable supply out of it for light duty stuff.

[@HighestRank]

ElectricalNovice19 I wonder how nicely it would do 4.5xV boosting while supplied a nice undervoltage, say like 200V from a varistor.

[@HighestRank]

ElectricalNovice19 I wonder how nicely it would do 4.5xV boosting while supplied a nice undervoltage, like

[@xcruell]

Never heard caveat emptor realted to CE before, i bursted out in laughter! :D Thanks for that one

[@wojciechtechtips1602]

That looks dope, I'm considering to buy one, is it possible to get a Samsung fast charger inside?

[@jdod64]

Isnt the fast charging just activated on the phone by tying the data lines together? Should be easy to jump them on the units usb plug. Also you probably could fit this unit with a better psu if you wanted. Wouldn't be too hard.

[@agvulpine]

What is the name of this style plug AC plug? Maybe you could do a history of british/european plugs, sockets and standards for us.

[@plmi1]

Europlug. en.wikipedia.org/wiki/Europlug

[@edgeeffect]

en.wikipedia.org/wiki/AC_power_plugs_and_sockets#CEE_7_standards

[@TheEPROM9]

Quite a neat little unit. Might have to get one. What video eding software do you use on your phone? Kind of want the recording and editing device to be self-contained for my KZbin stuff.

[@bigclivedotcom]

I use a Moto G4 with Open Camera to record and Vidtrim to splice sections if any editing is done at all.

[@TheEPROM9]

bigclivedotcom Thanks =-)

[@MrNikMills]

Yep. Singing Banananam in my head now. Thanks Clive!! :)

[@oggyosbourne]

Hi Clive! Nice video and that Motorola Charger a have the exactly same for my Motorola Nexus 6 with a european 2 plug on it.

[@bluerizlagirl]

If they are using the opto-isolator in analogue mode, then it is not surprising that it gets warm. When used digitally, the transistor will be either totally non-conductive (zero current through it) or totally conductive (zero voltage across it.) Either way, there will be no power dissipated within the transistor (maybe just a little bit, as it probably has a fraction of an ohm resistance in real life). But when the transistor is only partly conducting, there will be a voltage across it and a current through it, therefore non-zero power dissipation. So it will get warm. Perhaps you could attach a heat sink to it? You would need to put a mica insulator on top of the opto-isolator and extending over the pins, in order not to spoil the isolation gap.

[@JonathanWinterflood]

The TL431 should be an all-or-nothing shunt, although having the LED in the circuit might change that behavior; the LED current might be too low to properly saturate the phototransistor though, causing the same problem.

[@HighestRank]

bluerizlagirl nothing like a little foul backplate to add a little stray capacitance.

[@StarDustSid]

Good video, cheers. In your experience Clive, which bench power supply do you use or recommend?

[@bigclivedotcom]

Each has their own merits. I've not decided which is best yet.

[@StarDustSid]

Thanks. Let us know if you find a favourite.

[@ryanjcole]

Clive! Who makes your testers? Where can we buy them?

[@Gigachad-mc5qz]

i have a soldering station that comes with a power supply included. 15v 1A. love the soldering station but never used the power supply, mostly cause im starting out and lack creativity to make anything

[@drruncmd]

Thanks for that song Clive. Yup, going to have that in my head now! I would like to see some more power supply reviews and 'flash over' testing on the cheaper supplies. Have not seen a supply fail this test yet from you or have I missed a video? I love power supplies, only because like you, I hate surface mount components! Generally big chunky power supplies have both but probably 75% through hole components so can be 'easier' to troubleshoot and even mod to your liking. I have server power supplies which are built like brick s**t houses so may review one soon!

[@Seegalgalguntijak]

What does the "burn" mode on that Metrohm high voltage tester mean? Will we get to see flames? :)

[@agurdel]

"Mode select: breakdown, trip, BURN" You know what to do! And make it 4kV.

[@andrewwhite1793]

As in the intended mode of operation the user will be getting hold of the wires at the binding posts, The insulation should be reinforced, so the test voltage should be 3kV AC. I found this quote:- www.evaluationengineering.com/how-the-low-voltage-directive-addresses-product-safety Dielectric Strength Test This test usually is referred to as a hipot or dielectric-withstand test. It checks the electric strength of the insulating materials used within the product being tested. The test is performed by applying a sinusoidal AC voltage of at least 1,000 V for basic or operational insulation or 3,000 V for reinforced insulation at a frequency of 50 Hz or 60 Hz. The specification also allows a DC voltage equal to the peak of the prescribed AC test voltage to be used. This is paraphrased from BS 60950, but to see the actual standard you have to pay a lot of money.. or cdn14.21dianyuan.com/download.php?id=80665 ... for the UL version of the same standard.

[@skyalchemist0]

What is your opinion of those TS100 portable soldering irons running ~70 USD on Amazon?

[@SigEpBlue]

That supply falls into a difficult area of product quality: _almost_ acceptable. Just a few changes, and it'd be quite useful for those experimenting with USB/5-V stuff. I can't believe they're trying to sell these for $20, though. Seems a bit steep.

[@clemstevenson]

I've got the track "Ma Nah Ma Nah", by Peiro Umiliani.

[@JimFortune]

Did you buy the "no bang" power supply from Banggood? How disappointing!

[@HighestRank]

Jim Fortune I not good as I'm once was, but am I good once was as ever. Remember mains is over 9000 in Soviet China.

[@boonedockjourneyman7979]

Clive, like many KZbinrs, can’t think of anything better to do than buy crap, prove it’s crap, rinse and repeat. It got old during the EEVBlog Batterizer days. Clive, you’re better than this stuff. Go back to some of your work. It was great.

[@gedtoon6451]

When you review products that come with those two pin plugs. I would like to see you cut them off and fit a proper fused UK plug.

[@uK8cvPAq]

What about a resistor in series with the opto? Wouldn't that stop it from getting so hot?

[@bonobo8803]

Love your videos! I learn alot! It would be interesting if you took these crap products and switched out components to make them work they way they are advertised!!!!!!

[@absurdengineering]

The leakage “voltage” is a direct measure of leakage current. It is the leakage voltage divided by 10Mohm input impedance of the multimeter (or whatever it is). In your case it was seemingly 1Mohm so 90V/1Mohm=0.1mA. With a current shunt it came out to 0.2mA. Right ballpark. But be careful with using low impedance circuits for such measurements: they form a transformer winding. It doesn’t take much to induce 0.1mA in a coil of wire that’s close to other transformers etc.

[@VoidHalo]

Being that this is a 5V supply I woulda thought it would be perfect for TTL circuits. Unfortunately with 4.6v I don't think it would cut it. Think I'll just stick to my 9v batteries and a 7805.