Let's take apart this interestingly shaped LED lamp which I think is based on a traditional compact thent design called Plumin which was popular with Architects because it was a different shape from conventional lamps. Now a traditional version of these Led filament lamps. normally just as one filament. this one does look as though it's got two unless it's one that's looped backwards and forwards and then back through the tube so it may just be one filament.

We'll find out cuz we're about to open this up. But before I do that, let's plug it in and test it. So I shall plug it into the Super Shady Chinese Factory tester. It lights up um, and it shows a power of approximately 6 WS That's reasonable enough.

Let's take it apart and we'll see what the circuitry is inside. So is this sponger going to open this? Let's Zoom down it and get a bit of closer. I Do see. Oh tell you what else we should do is this glass or plastic? Let's do a Jerry rig everything.

It's plastic. Excellent. That's uh, good. From a sort of not breaking aspect, but not great from a bursting as you know, a burst into flames aspect.

Is this going to come apart easily? This may not come apart easily, but you know what? I buy these things so that we can explore them internally and they often get broken in the process. I Do try and put them back together again afterwards, but sometimes they are destroyed completely. Let's see if I can get this out intact. Tell you what else I should do I should remove that little rivet at the back because that will also clamp down on the wire onto the circuit board.

That is. It pinged out. It has literally pinged out. Let's see if this gets me any closer to opening this.

There we are. There's a little driver board, right? Let's cut a wire that's holding this in place. and here's what we have. This does look.

It's two filaments in parallel. The look of it right. Tell you what I shall reverse entering of the circuit board and we can explore it one moment. Please, Reverse engineering is complete.

Let's explore. Let's get down and personal with this circuit board. The supply comes onto the circuit board via a very high value 220 ohm fusible resistor and goes to the Dir fire, but it also has a metal oxide veristor across that and that does hint that it is a dimmable, uh light. The supply gets full wave rectified and the unsmooth section goes via this load resistor which is intended to keep the triak latched on that goes through half of this circuitry.

This is an SM 2082 EG G which is a linear regulator, but it's got two sections and that can be used in multiple configurations, but in this instance it's being used with the the dimmer latch load on one half and that interacts with the other half as I shall show you in a moment off circuit board here there is a capacitor and uh, that capacitor is charged via this diode and it's also charged by the Uh linear regulator here, which sets the maximum current that can go through that circuit. Then the current goes through. the L s comes back on here, goes through this mystery component 1 1012 and then underneath it says 102. Uh, and it's got a little capacitor I Think that's a dynamic linear regulator to assist with the dimming.

Anyway, let's take a look at the schematic noting that there are two Uh resistors here for the one programs urrent through the LEDs and one programs that current through that load resistor. I did actually power this up with without the LEDs to see what power it Drew and without the LEDs active, the load resistor posed a load of about 1.5 Watts or about 6.5 milliamps. Let's get down a little bit close to this. Oh, too close.

That's better. Here's the supply coming in. there is that fusible resistor I'm not sure what that says in Chinese I could have translated it, but I'm probably sure it says something like fusible resistor. There's a loocks of which they don't show in the cry.

There's the Bridger far. Note that this is the plus Supply and this is the minus effectively. but they've shown an Earth symbol. Don't just ignore the Earth symbol, they're just using that as a zero volt for the circuit reference.

I've drawn the little preferred block here, which just basically shows circuit, ground or circuit zero volts. There is the resistor. This is a load resistor a little powerful res high power resistor 15K which I measured as dissipating 1.5 wats when I H powered it without the LEDs connected cuz it was active all the time. But it isn't active all the time and that's on the unsmooth side.

But after this diode, um, it goes and this capacitor is quite significant. It's not just for smoothing the Ripple across the LEDs I reckon that the linear current regulator at this side, its main job is to limit the current into that capacitor so that if this is being dimmed and the sine wave is effectively set to half intensity so it's only active for that part of the sine wave, then that capacitor will only get a given amount of charge versus what's being uh used by the LEDs and there is an extra little component in here. the Vas1, Um, and I'm wondering now if that, instead of being a fixed current regulator I Wonder if that dynamically reacts to Ripple so that if it sees that the Uh current flowing through LED it's high enough to actually discharge that capacitor very quickly. When it's you, turn the dimmer down.

Um, it actually dynamically reduces amount of current through the LEDs until it sees lash ripples. It's basically monitoring the current through LEDs versus the stamina of this capacitor which is being current limited. uh, when it charges via this bit. The circuitry.

The extra bit of circuitry down here is interesting. The arrang of these two resistors. Now, this is just a dual linear regulator. It can be used.

You can actually parallel the Uh connections and you can just use it as a high current regulator. Or you could have two sections of LEDs. You could uh, have Uh one on each half, but in this case they've got the one half is doing the Uh load resistance which just keeps that triac latched on. But note that this Uh has sensing voltages in the input of 6 volts.

and the case of the 20 ohm resistor. Let's get the Kink calculator in here. the current that it's going to regulate to is going to be 6, which is the voltage it's looking for across the resistors. Divided by the 20 ohms, it's going to be regulating to about 30 milliamps, which kind of tallies up with these filaments which incidentally are in parallel.

So that would be 15 milliamps per filament. which is about right. However, note that connected to the top of that resistor is this 91 ohm resistor and that is Uh. 6 divided by 91 ohms equals Uh, a current through that resistor of about 6.5 milliamps, 6.6 Uh, which times the 240 volt RMS that we got here gave roughly the 1.5 is Watts.

Well, 1.6 in this calculation. Um, But it's interesting to note the reason that resistor is tied to the top of that one is because at when these are actively limiting current, the voltage across that resistor is about 6 volts. So as the current reaches up that level, it starts linearly regulating it. But because when the LEDs are conducting current, this resistor is not actually needed to be active and it would just be wasteful if it was just it would just be dissipating extra heat.

So what happens is when the LED section circuitry is passing enough current to regulate the voltage cross here Rises up to 6 volts and it means that very quickly. Well, very little current through that, if any at all is needed. so the resistor effectively turns off while the Uh capacitor across the LEDs is charging up. It's very interesting circuitry.

I Am Uh, Finally make a bit more sense of the Uh, this little chip, its function and why it's got the capacitor. I Think it is a dynamic uh, self-regulating linear current regulator just designed for dimble chips. Very hard to say without Uh getting a proper data sheet in in raw English but that is it. Uh, it's an interesting circuit.

it's an interesting light. I'm kind of tempted. just make it a very simple power supply cuz I Rather than actually like the room with it I Quite like it, just as a gentle glowing ornament. I might just add some resistors erect for and a smoothing capacitor and try that.

But anyway, that. is it. Uh, interesting circuitry and more interesting to actually make sense of this little chip that has been put in line with the LEDs for that extra dimming functionality. it's very interesting.