Inside a '4kW' ebay power controller with schematic.

This is a look at another Chinese industrial control component.
At first glance this phase angle power controller has a strong case resemblance to the common 12V chassis power supplies. But this is a beefy triac based mains power controller for things like lamps, heaters or some motors.
It has a few notable features:-
Nice case, beefy triac (one of the biggest of its type if it's original), extra circuitry to give greater stability and output symmetry at lower levels and a bit of effort to ensure that tracks are robust enough to handle fault conditions.
It does have two slight issues. A glass fuse instead of a ceramic one and a seemingly excessive resistor value in the snubber network. 4700 ohms as opposed tot he more common 100 or even 47 ohms.

[chuuni]

I've always wondered why those diac/triac dimmers can't dim evenly down to complete shut-off. Thanks a ton for explaining that!

[HennerZeller]

I have myself sometimes used bridge rectifiers different from their 'normal' use because I needed such a particular diode arrangement and they happened to come in a cheap package like that.
Of course the meaning is disguised just seeing this as rectifier symbol in a circuit.
It always makes sense to actually write out the diodes in a schematic to see these kind of hidden (rather interesting in this case) meanings.
Thanks for the teardown and detailed explanations about your findings.

[cliffordwagner]

It might be informative to see that power supply connected to an oscilloscope comparing the waveform while using the 4k7 in the snubber to that of a 100 ohm resistor. I wonder how it changes the snubber performance.

[extraglutenplz]

Hey Clive I know you've done a computer power supply tear down but I was wondering if you could compare a cheap PSU to a notable good quality one....in terms of quality of components and circuit architecture.

[youtuuba]

For what it is worth, a company I used to work for made a whole series of TRIAC based DC motor controllers, and the snubbers were all 47k and 0.01uF (10nF). I never questioned how they got those values, but the circuit and TRIAC worked fine.

[crazyirishman]

The great Resistance on the snubber is effecting the time constant of that of the RC configuration (Making the charge time longer). This most probably reduces stress on the capacitor when there is a high inductive load present .

[NicoIsntHere]

I have no background in electrical work and struggle to wrap my head around watts vs amps vs volts (basically anything electrical) but I still binge watch these lol. Great presentation and ability to talk fluidly!

[simontay]

I bought one of these after watching Clive's video. I added an earth wire to the screw and added a large inductor to the output. Also insulated the top and back of the heatsink because it is VERY close to the case.

[jackiebutler]

I use one to control the heating element on my pot still, it works a treat and the controller only reaches 40-45C after 3 hours use @2600W load which I think is acceptable and definitely better than I expected when I was installing a cheap Chinese component.

[Mekchanoid]

I can't admit to understanding all the electronics, but was delighted to hear that this regulator is designed to deliver smoother power at the lower end. My Ryobi drill is very spluttery and rough on slow RPMs and I'm really hoping this will help that. Also, several units of this type have been condemned as death traps, with circuit boards virtually touching unearthed casing, so I'm glad this thing appears to be relatively safe (despite looking hideous and having only one mounting hole on the front). Thanks for the clear and meticulous breakdown.

[bogywankenobi]

I had to watch the bridge rectifier explanation twice before I got it. (I'm getting old.) But that is quite genius. Thanks for the explanation.

[hightensionlabs]

Thank you for mentioning Amateur Radio it’s much appreciated.

[Andromedan]

As a radio ham, I don't actually use those bands (2m/70cm personally, I know some HF guys though), but the only thing worse than an unfiltered dimmer is those awful powerline ethernet gadgets. Great way to turn all the house wiring into a giant antenna for digital noise!

73s, 2E0GXE

[foogod]

This is why if I'm drawing out a circuit with a bridge rectifier, and it's not immediately obvious how it's being used, I do _not_ draw it as just a "box" like you did. I draw out the full "diode diamond" instead, because that often makes it much easier to see what's going on if people are using a bridge rectifier in an unconventional way (i.e. not actually as a rectifier), which does happen surprisingly often I've found.

[Shaun.Stephens]

I see that the youtube algorithm has chosen this video for this week. I watched it a few years back but that was on my other account so decided to watch it again. I'm pleased to say that, having watched Clive's videos for a several years meant I understood this so much better this time around. :) Learning by osmosis is so much easier than studying.

[TheHaerlings]

The label is very logic, it's a very efficient way of supplying the sticker for your case, you peel of the blue part, then you peel off the sticker from the blue foil and stick it to your case where the module is installed. By doing it this way they are 100 percent sure that the sticker doesn't get damaged during transport.

[neilphilip]

Superb! Like a previous comment I wondered about the poor performance of dimmers at low levels and now I understand why!

[LazerLord]

Question: Would I be able to use one of these to power the heated build plate of my 3D printer? It's essentially a 1.8 ohm resistor, and I'm not sure if something like this would work.

Of course, it would trip a breaker if I turn it up too high, but I'd be running at ~24Vrms and ~400 watts. Does this sound reasonable?

[lumpyfishgravy]

Another point to note about fault conditions is the extra solder they have put on some tracks. In fault conditions this will sputter or could even create a vapour cloud which shorts out *everything*. Fault condition testing can be quite fun actually! Place a sheet of blank paper under the board to catch the sputter, then hang it on your wall!

[crocellian]

The Chinese have several "standards" like the EU DIN packages. In many cases, the frames are the protective earths. Cheap, fast, safe.