High voltage LED tester with VERY clever circuitry (and hidden features)

It literally took me three evenings to reverse engineer this unit. The circuitry is very complex, but also very well designed. Unlike the previous horrifically dangerous unit I looked at, this one has the outputs isolated from the incoming mains supply. It's still 300V though, so can still give an odd DC zap if you get complacent with it.

The soft start is very simple, but very neat. The regulator chip that limits the current through the LEDs is very impressive in that it can handle a short circuit as standard.

There were two extra features I was unaware of. A low voltage mode for finding polarity of LEDs without risking damage to them, and a higher current mode that steps up from the standard 20mA current to 50mA after about 10 seconds when you are testing higher voltage LED arrays.

There are lots of clever quirks in the circuitry that were quite enjoyable to decipher. Especially the way the main power supply chip is actually an LED driver being used with an opto-isolated feedback hack on its overvoltage protection pin, normally used for detecting an open circuit load.

I did test the other unit, and it too has the 18V feature selected in the same way. But it doesn't have the higher current mode.

To toggle between the 300V and 18V modes you hold the leads together until the display flashes bars.

Very clever design. Both frustrating and a treat to reverse engineer.

This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty.

#ElectronicsCreators

[barrieshepherd]

Full marks to the design team and to BC for persistence above and beyond, and finding the hidden easter Egg function . Who'd have thought that testing a LED could get that complex!

[simontay]

15:37 "Sorry if this is boring" Its NOT boring. Its very interesting. Im glad you have the patience to reverse engineer it so we don't have to.

[daleomiller]

Never apologize for your complex videos. I am *not* an electronics person, but you explain things in such a way that even I understand. I love your videos.

[mikkovirtanen]

I can hear the happiness in the voice when mentioning that "they are professionals", put a smile on my face.

[gd.ritter]

it boggles my mind that the current limiting can kick in fast enough to stop the 300v output from frying a single LED. that amazes me how some of these things work.

[cremvustila]

clever is not boring, your effort is much appreciated, Clive!

[KeritechElectronics]

Pretty complex and what's most important, there's galvanic separation. I completely didn't expect that, and I appreciate it so much.
I'm pretty sure you could test Zener diodes with it as well.

[piltdownman]

Dear Mr Big, can I call you Mr Big? Not boring AT ALL. Thank you so much for bringing us the more complex circuits. I appreciate your hard work, on our behalf.

[iaov]

This is not boring at all. I was amazed every day for the 45 years I worked in the electronics/ electrical field at what smart people there are in the world who think up and build the incredible technology we live with today. I am also amazed at your ability Clive to reverse engineer these circuits and explain them so well to us. Thanks brother!❤❤❤

[clovislyme]

I never cease to be amazed at the many instances of ingenuity, complexity and utility that can be purchased for such low prices these days.

[PeterEdin]

I never thought I'd hear "very good" and Ali Express in the same sentence 😂

[ZeedijkMike]

You condensed those three evenings into 23 very enjoyable minutes.
Nice to see some good and clever design. Always nice when you can "mis-use" a chip in a clever way.

[DaveCurran]

I like these deep dive reverse engineering videos, particularly when there are clever bits to the designs.

[txbrent]

Warms my heart to see Clive be impressed with the design of something which was unexpectedly good

[markpunt]

We are blessed to have not only your extensive knowledge but also your patience and tenacity. Thank you😊

[harriehausenman]

I prefer this format. Thanks for taking the time and putting the effort in. Much appreciated!

[memejeff]

Extremely interesting teardown. This may be one of the most inpressive devices you have torn down. Never would have expected such a clever way of repurposing mass produced LED driver chips.

[shaunclarke]

A nice bonus for you by finding new features from looking at the hardware.

Your hard work and dedication paid off.

[tamtgirl]

i actually like your more "in depth" videos like this. most of the time i'm here to learn something! the "dumd" tear downs are fun, but i'd rather find out how thing work in electronics like this

[Onio_Saiyan]

"Let's take a look at a completely different high voltage LED tester." My first thought was "Would love to, dude!"
Sat here in my pajamas and under six blankets because I have a migraine and need a low-action, highly interesting thing to watch and my suggested sends me a banger.