You're probably all familiar with these lamps and I've taken a few apart in the past and they had different circuitry so this isn't a repeat video as such because the circuitry in this one I've checked is different again, so it's well worth investigating. So this is the classic rotating LED disco lamp and they normally, well, it says it's a three watt lamp, but it's actually showing 1.9 Watts here on the meter on the anti 24 milliamps 0.3 power fighter, which is not unusual for the type of power supplies they're using. these and the idea is you've got three LEDs behind here red, green, and blue and they shine through this rotating Dome The dome in this one is very diffused and you know what? It seems like they've maybe chipped out a bit too much in the dome. Let's unplug it because a clearer Dome would have produced sharper images.

But that's okay. I shall get the hand tie out of the way and we shall open this. We'll get straight into it. so the Doom comes off as they often do, with a single screw in the end, which is on a shaft that is connected to a little DC motor underneath.

Now, you can already see there's components on this circuit board. Let me Zoom down a bit. Uh, because it looks to All In terms and properties as if the whole power supply is integrated onto the circuit board alongside the LEDs which is interesting. They normally have a separate power supply either.

the capacitive dropper in that very odd one I got super low power, but just because a capacitive dropper is really not suited to this. High current LEDs but the other ones usually contain one of the little LED drivers I'm just seeing I've got one handy I Do not have one handy, but the ones you'd normally find in the base of Gu10 lamps. Yeah, so we've got a couple of capacitors on this side. it's not an aluminum core.

PCB We've got an inductor. we've got the and I was going to say transistor. It's probably a dedicated integrated circuit for a buck regulator. and as usual, we get the motor tapped across.

uh, this Led here. Sometimes you rotate the motor, it makes the LED light up. It does. It's a green LED and uh, turning the other way usually makes others light up.

if you do it fast enough, at the risk of Breaking All The gears in the gearbox radio. well, you know what we do. Now let's take a picture of it and then reverse engineer it one moment. Please, Reverse engineering is complete.

Let's explore. So this is based on a Kw10l chip. I Could not find a data sheet I found a similar chip ultimate land I Could work out its function and then the circuitry that was around it to draw the schematic. But to start with we have live in neutral command.

The neutral is the whole negative reference for the whole circuit. It's almost like the zero volts the live comes on. Via This improvised views a one amp diode. It's got a death beaming capacitor 6.8 Megaforce and then it goes to the little Buck regulator chip and they've really cut that down.

It's three pins. It's kind of ridiculous how they manage that and it uses an inductor one millihenry inductor to drop the voltage because it monitors a voltage to this capacitor here. 220 Microfarad 25 volts. Now, this is a 5 volt regulator, but they've stuck a Zener Diode in here.

5.1 volt. Just in nudge it up to 10 volts. and uh, that 10 volts is then applied across the LEDs via this 50 Ohm resistor which is upside down. I Wonder why they've it looks hand soldered like they've added that in afterwards.

And you've got the three LEDs in the series. You've got the red, the blue and the green. And because there's three volts across the blue and the green and the blue and the two volts across the red that gives about say eight volts to drop. So it's dropping two volts across this resistor, which equates to about 135 milliamps through the LEDs.

The Uh motor is just tapped across the green Led. The probably the reason they probably done that is because the green is the brightest of them all, so it's not going to match too much that a little bit of the current has been cheated away 25 milliamps through the motor. The bulk of the components are in the front and circuit board at the back has the two capacitors, the little switching regulator, and the one millihenry inductor. There's also worth of note: the dotted line here.

You can see the outline here as well. that's a heat sink of the sorts. It's not really going to dissipate a lot from these LEDs because they're being run at less than half the normal current. but uh, this.

basically this copper triangle just goes underneath the LEDs just to try and take some of the heat away from them. Let's bring in the schematic: I Do think there's anything else worth mentioning on that? No, there isn't Okay, let's take a closer look at this. So there's the supply command, the improvised fuse, the standard one amp diode, the 6.8 microfire death beam capacitor, and then it goes to this little chip. It's this switching input to that chip.

The chip. The one thing they seem to have added. not sure if this is standard. they've added a one ohm resistor there, but uh, this chip will basically pulse this in Doctrine It's got current sensing built into it and it poses the inductor and when it does so, it charges up this capacitor.

Uh, the field is built up, then doctor, then it turns off, and when it collapses, the capacitor is also charged from the collapsing field via this uh flyfield diode, which then bypasses from that end of the inductor over to the other end of the capacitor that then tops capacity up to 5 volts plus their Zener drop. Here, they've added that 5.1 volt Xenron to add on to that Uh existing 5 volts to give roughly 10 volts. Then there's a basic 4k7 load resistor I Think that's purely so. If the LEDs go open circuit, it just provides a slight load for circuit stability, and it's quite clever.

The circuit here, as well as monitoring the voltage in that V plus pin, it also uses that as the supply for the chip. It uses the current switching pin as the Uh ground reference. a zero volt reference the internal circuit in the Chip And that feedback as the plus volt. Supply So it's going to see roughly five volts there, which Powers the chip.

Um, that's also a standard uh, high-speed Es1j, Es1j. They've just used both here. uh, diode. And then it goes to the LEDs.

It's got a 50 Norm resistor. that's the one that's upside down. It's got the red, blue, and green. so two volts across the red, three volts across the blue, and three volts across the green.

so it adds up to about eight volts. And then they're dropping two volts across the 15 Ohm resistor. and there's the motor tapped across the green. LED with its 25 milliamps.

That is it. It's a very simple circuit. They've really cut this down to the bare minimum. I Guess Ultimately, it's a cost saving exercise, so that is it.

Uh, the disco lamp all back together and working. Uh, that has basically oh I should have mentioned the one Milli Henry inductor I took it out of socket, tested it 4.6 Ohm I didn't take this the only component I couldn't give you a vowel for I'll guess it's maybe 100 non-fired is this capacitor? but uh, that's it. The super streamlined uh disco lamp where they basically removed the little current regulated power supply and they've created a 10 volt Supply without resistance. Here's the LEDs just to keep the circuitry as simple as possible.

it's very minimalist. It's very cheap, but it does work.