A while ago, i featured the dubai lamp and it caused a lot of controversy because uh this is a lamp that was not available to the rest of us. It was only available to the people of dubai due to a deal between phillips and the ruler of dubai, who said he wanted the most reliable longest lasting, most efficient lamp in the world. They created them custom lamps in one two and three watt ratings. This is a two mark rating and for those of you who said, oh, we have those uh locally at the local supermarket for ages.

This is the one you have. It's got four filaments, it's four watts. This one is actually brighter. It's got 12 filaments.

No, it's got eight filaments and is rated two watts, so basically, four filaments per watt versus one filament per watt and this and it just means that under running the leds and the choice of phosphor makes this much more efficient than this. You have this one. Well, actually, no you don't. You now have this new one by philips, which is for the rest of us.

Let me read: what's in the packaging first 3000k color temperature for this one interesting color i'll, show you it. Uh 4 watts is equivalent to 60 watts. 840 lumen, which makes it slightly more efficient than this one, the original dubai lamp. It has some notable things.

Inside 60, less energy compared with standard phillips led bulb 50 years or 50 000 hours that, if you calculate it out, works to roughly about three hours a day. If you want an actual year, 24 7 life span. It's five point, seven years, fifty thousand hour uh. Fifty thousand switch on off cycles, which uh the circuitry is going to be pretty robust in these i think uh, instant lighting, not dimmable, can be used in enclosed fixtures, not suitable for use in the rain, and then i don't know what the symbol is.

I do not know what this symbol down here is hold on, i'm going to zoom up in it and focus on that, and you can tell me what you think that is, i don't know it looks like maybe an overhead light. Is it just means it's not suitable for illumination of uh walkways or something like that? I'm not really sure it's a new symbol to me. Let me put this back down and zoom out and then focus back on the subject in hand. Right say what let's open it up: let's plug it in so it is quite unusual.

It's got longer filaments than the original dubai lamp. This one is rated. The 4 watts just double checking that yes, and it has eight of these longer filaments, um and uh. Let me plug this in.

Let me show you lit: that's the best bet. Isn't it so i'm going to plug in the hoppy meter here is going to bring it in and show you the power rating and you'll see it's quite an odd shade of white. This is like this is compared to sort of daylight, because that's a typical lighting i use at my bench. The color is a worm white, but it's almost like a shade of cream and i've got a theory about this because they do specifically say eye comfort.

It's optimized for that. I'm just going to give this a swipe and see if it flickers no flicker at all. Let me just uh demonstrate that on screen. Well, actually it does look like it's flickering, but that's probably the rolling shutter effect, uh 4 watts 3.84.

To be precise, um power factor of 0.5, which is fairly typical for led lamps. It's not so critical because they're, not a super duper high load. So the color - i would say this is - is a soft white biasing very slightly towards the green area of the spectrum, which makes sense, because the human eye has a peak sensitivity of around about 555 nanometers, which is a sort of um, aptly green color. And they might be aiming for that uh just to improve the efficiency, but also to make it softer in the eye, because that's where a lot of the visual data in the eye will be resolved right, tell you what uh we're here to take this apart.

We do that a lot in this channel stuff gets taken apart, so uh, i'm gon na try popping the little stud at the bottom. Here i shall zoom in a bit for this, so we can watch the blood gushing from my hands. When i have a terrible incident, it can happen. Blood has been shed in the channel, it occasionally happens, it's called workshops.

So that's a little stud out. The end am i going to be able to nibble into this. This is where people also suggest. I use a dremel.

The dremel does work, but it makes a bit of a mess. I'm just going to nibble it away like this and see where we get. It might be a disaster i did say i'd zoom in i did not zoom in there we go. I have fixed that now for those of you who also brought up the subject of the phoebus cartel, how there's a lamp in america in a fire station that has burned for ages, and they could have made lamps that last forever.

In reality, the 1 000 hour thing for lamp life, the original tungsten lamp. So this has got a plastic shell in here. That is making this quite hard to nibble into, but the phoebus cartel the 1 000 hour. Life is a compromise.

You can make a tungsten lamp that uh lasts much longer the building site, the rough service lamps last a lot longer by under running the filament. So, instead of being a nice cold, crisp white light, it's a deep golden light, but it puts out a lot of energy in infrared area of the spectrum and not the visible layer of the spectrum. So you end up with a lamp that lasts for ages, but uh exponentially longer, but the efficiency tails off dramatically. So if you consider the uh 100 watt lamp of the original tungsten ones, if you ran that 24 7 um and you only needed to say, for instance, you only need about half that amount of light, but you use the the longer lasting, lower running lamp.

That would cost you about 100 euros, 100 pounds a year in electricity cost. This is this has got a little shell in it. That is different to the last one, or i should mention this is made in china. Where else you would expect to make all stuff made in china for everybody who criticizes china uh your your computer's made in china most likely everything is made in china yeah, it's not an ideal situation, but uh, but it is what it is yeah.

This is a quite uh tricky i'm going to persist, though, i'm going to keep peeling away at this. Oh now we're getting into the uh the glue at the base of the lamp, the bit that holds into the lamp cap. This is where it bursts forcibly. In my hands so yeah, the phoebus cartel was a standardization apparently between the manufacturers.

I don't know, did it really exist but um it was. It wasn't just to fix the life of lamps and make profit. It was based on efficiency of the lamps that compromise between the light output versus um the fish. This is more suction than i was expecting.

This looks like i can see an inductor in here. Is this a switching power supply in this one? That's a change. A little buck regulator, perhaps let us peel the last bit off and slip this off. Let's give this a squeeze and a big pair of pliers, scrunchy scrunchy squeeze the plastic, lift it off.

We have what looks like a little buck regulator. Right say what it's time for some reverse engineering: a little bit filtering circuitry as well uh. One moment please it has been reverse engineered. But before i show you the schematic here is a bizarre coincidence.

I decided to power up the lamp just to measure the voltage across the filaments, because i needed that for a specific reason in the schematic that took the longest time to reverse engineer just for this strange off data sheet oddity. But i connected the lamp to this. Capacitive dropper, which is based on a 680 nano farad capacitor, watch the power rating and the voltage across leds, but the power factor and the current and everything. Let me just plug this in so the lamp lights up.

This is it with a capacitive dropper, um 3.86 watts, which is the other one was 3.84 29 milliamps milliamps, the other one was 29 milliamps and a power factor of 0.53, which is very similar. This thing has gone over range, hello, let's uh select or i shall reset it and uh select the voltage and it's showing 200 volts. So each of these filaments there's clusters of them in parallel and then in series. So each of these filaments is dropping 100 volts, but there's two sets of three as far as i can see in series, and that means that that it's 200 volts across them, okay time for the drawings and continue so on one side of the circuit board.

We've got an 18 millihenry inductor, which is used to actually limit the current through the leds. We've got. The incoming supply comes via 2.2 ohm resistor as a fusible resistor, there's a 6 to 8 nano farad, 275 volt ac capacitor across the incoming supply and a metal oxide rest on the other side. Then it goes through the bridge rectifier and it charges this capacitor.

3.3. Microfarad 400 volts up to about 330 volts this inductor and a resistor one millihenry three ohms is actually in series on the dc side. With that, that's the component side of the circuit board. Well, that's the through-hole component side, here's the other side! So here's the incoming supply live and neutral.

There's the capacitor pins, there's a metal oxide varistor appears to be, and then it goes to the direct fire comes out. There is a track on the other side uh going over to here, where we've got the inductor and series of the positive going to the capacitor and then a metal oxide varistor across that i shall just add one small minor, pointless technicality to this. There. That's a minor, pointless technicality has been added the circuitry, that's switching, it is a uh pt4554 uh buck regulator with a couple of our parallel sent resistors and it's got the classic capacitor across the leds, plus the diode, and then a couple of discharge.

Very high volume discharge, resistors and then they're just basically going across the leds, which are here over to here and that's about all there is to see it should be a simple circuit. It wasn't a simple circuit to reverse engineer, just one little thing that went horribly wrong in the reverse engineering of this i'll. Give you a look at the manufacturer's data sheet: powtech uh. Pt4554C.

I don't know what the last letter was because trying to scratch the lamp cement off. I rubbed across that it looks like an oh but uh. It's that's not a valid component. It's either c or d.

I think it's a c. Here's, the circuitry very simple bridge. Rectifier smoothing capacitor the usual arrangement, but notice the hv line, which is powers this chip going straight up to the full supply rail. That's the bit that screwed me up.

Here's the actual circuit diagram. The incoming supply goes via that 2.2 ohm resistor, there's a metal oxide varistor across it to clamp any spikes and then there's a six to eight nano farad 275 volt ac capacitor. It goes through the direct fire comes out the other side. The positive gets filtered through a 1 millihenry choke with a 5.1 k resistor across it, and it charges up this 3.3 k at 3.3.

Four invoke capacitor, which also has a metal oxide wrist across it just to protect against spikes and glitches. So this will in circuitry terms, be round about the zero volt reference, and this will be about uh. Well, what would that be? Let's go. Let's go for a euro voltage 230 volt 230 volt times 1.41 will give us uh that's going to charge up to say 325 volts.

This is important to know, because there's a weird deviation from the normal circuitry here is the little chip. That's doing all the work and it basically turns on uh in the sense that it pulls this pin d for drain down to negative current flows through the leds from the positive through the inductor, and because it's a got up. It's not got a magnetic field at that point in time. It pushes back the back emf and it limits the current flowing once it reaches a certain threshold sensed by these two parallel resistors 39 ohm and 12 ohm, which gives about 9 ohm equivalent.

It turns off, but because this was positive - and this was negative - then it turns this becomes negative. This comes positive and actually as the magnetic field in that collapses. It goes through this freewheel diode so that both putting the magnetic field into it and when it collapses and it's turned off - are both used to power. The leds.

There is a 220 nano farad capacitor across the leds, that's about 200 volts across here, and also these very high value 2.2 mega ohm resistors to them in series uh to make sure those leds go out quickly and don't fade away slowly. I presume, but here's the oddity, the data sheet shows the hv connection going up to the 325 volt rail and i honestly i i was like probing about - and i was saying oh that'll, be to the positive and i was probing to the positive, not getting anything And it just nothing was making sense. I ended up removing the component uh, which was quite tricky because it was well glued to the circuit board and discovered that it was actually connected to here instead, so that isn't used that line there isn't used it's actually connecting to the bottom of this circuit, and I thought can they do that and, i suppose, ultimately, 325 volts minus the 200 volts across leds means instead of this chip seeing 325 volts, it's now only seeing approximately 125 volts across it. They may have done that as a clever trick just to take strain off this chip.

That's quite neat, if that's what they intended to do, i don't think it's a mistake. I think they actually meant to do that, but it's not showing the data sheet. I wonder i wonder how they made that decision to use in a non-standard way like that, a bit worrying to actually use a component in an off-label way, but i guess they probably just decided they probably sculpted everything and just decided. Well, that's going to take a lot of strain off this chip, but there we go.

That is it! That is the uh dubai lamp for the rest of us. It's the philips! Well, what do they call it? Uh phillips white, our ultra efficient light. Oh, this was expensive by the way this was about 10 pounds plus v80, so it came up to 12 pounds this lamp, which is a lot more than a typical standard lamp, but i suppose ultimately the place that this is going to win the application. It's going to win is, if you use it either as a if it's you find a nice color for reading, but also locations where are is quite hard to access lights or you want a decent amount of light, and it runs a lot of times say you Had a corridor in the house that you had a couple of lights in it that might make sense to put these in i'm a bit surprised, i'm slightly disappointed at the circuitry.

I must admit i was hoping it was going to be the dubai circuitry. I thought. Maybe even in this day and age, they might possibly have gone for the linear regulator. Approach like many of the others do, but this one.

It just strikes me as it's not get that extra double layer of redundancy the other one has. But having said that, hopefully it will be staying fairly cool um, but it is ultimately just a standard buck. Regulator like you might find possibly not this lamp, but it's quite interesting, strange creamy color, but uh there we have it uh. The 4 watts equals 61 840 lumen, oh color, rendering index 80, so not great, but that's common with the led lamps.

The color rendering index is how well it renders colors across the full spectrum with uh the led lamps. You've got blue leds and stimulating phosphorous. To add the red and the green components, it's not a perfectly linear spectrum, so you don't get absolutely amazing, color rendition, it's just like the early fluorescent tubes as well, but that is just one of these things. It's the compromise you make for the efficiency, but a very interesting lamp.

It was certainly well worth taking apart and exploring and uh. The construction is very different and uh that little twist in the circuitry that took me by surprise was quite intriguing and took a bit of working out, but there we go, that is the philips ultra efficient lamp.