Here's an oddity: it's a string of festoon lamps and you think it just looks like standard lamps. Until You realize that it's got a USB connector on it and this is actually powered from a five volt. Supply And if you unscrew the lamps because you can in this instance, then they do have standard E27 bases, but they are designed for level the juice. It's also worth mentioning that the globe of the lamp is plastic, but the actual support inside is glass.

That's beard. We'll take one of these lamps apart, but initially I shall plug it into a USB power supply and we can measure the current. There are 10 lamps in the string. Let's go to 10 lamps in the string.

Yes, there are 10 lamps in the string if I plug it in here. initially, it doesn't light. There's a little Touch button here. if you touch the touch button.

This slowly ramp up to full intensity and the current draw is 950 milliamps. So let's say one amp about 100 milliamps per bulb. That's quite low. That's half a watt per lamp.

not sure how much that's being disappeared across the filament. The remote control also lets you Dim them down or turn them on and off and it fades up and down. That's all it really does. I Don't know if there's a resistor in here, but we shall find out.

First things first, let's take one of the lamps apart. so I shall select a random lamp to be destroyed and unfortunately, these are crimped. I'm just going to put that battery pack out the way. These are crimped in quite tightly.

So I'm going to have to actually do the usual thing and peel the base off the lamp. That's okay. I shall pop the base connection on it first because that will release the wire. Let's Sim down this mainly so you can see the Carnage when I have a terrible incident.

So if I try and get the little rivet pin out at the bottom, there it is that's released one of the wires. Is there a resistor in there is a resistor? Yes, there's a resistor. That's interesting to note. Okay, I'm going to completely destroy this lamp holder now by peeling into it because it's the only way to get off.

Although this is a plastic housing, it is super well crimped and they have an interesting tool for that that you basically drop the lamp into, pull the handle over, and it crimps it. I Have won an order from China Hopefully it will arrive because uh, I decided to make some lamps just for fun. So let's peel this up and just see how far we get. Stay in the shot here so we can.

Marvel At aforementioned Carnage there is the wire come out the side that's connected onto the housing. Oh, it's quite a thin wire. Then again, it's not really taking much current and it's certainly not taking full means of voltage. I wonder if it's just looser if it's right up to the top I Didn't see it going right up to the top I Don't know if it's just basically springing against the side here.

Hmm, here's a tricky bit: I don't have to worry about the glass breaking this time. The lamp has marked one more five, so let's get this out here. Oh, the last bit is just proving irksum as sometimes they do. Here we go.

The base is off, revealing the plastic housing the glass support for the filament and it is pressed into a little plastic grip with a resistor with a value of oh, that's a multi-band resistor. Hold on. Let me just see if I can see this or I'll just measure it. Uh, brown, red, black, gold.

The gold is a divider. So and is that 12 ohm? I think it's 12 of them? Yeah, I think it is 12. Or let's measure that. Let's get the emitter in and we'll set it to 200 ohms.

It's good that there's a resistor inside it. I did test this at five volts. It drew a lot more current than in the string. so I guess the wiring must be also.

uh, having an effect on that. 12 Ohms is 12 ohms. Okay, that's useful to know. I can pop this back into its little housing if my crimping tool and the bases that I've ordered come back from China can actually repair this I should be able to put this lamp back together again.

In the meantime, let's take a look at this. So how is this put together? Is this going to come apart easily? I shall sweep all the shards of metal off to the side before I impale myself on them I'm going to guess that it splits around about here. it might be glued together if it is glued together. I shall pause and take it apart in a more controlled manner because I mean you have to will.

it might not be controlled I don't think that is a separate base that comes off there I Think this is really, uh, clamped in our side. The wire there. um, where is a pure pliers? Let's squeeze it firmly and see what happens. You'll squeeze it like oh, that.

that sounded crunchy. that was crunchy I Think this is a good thing. It is kind of a parting. the story of that.

speaking loud poppy noises through the speaker. the microphone doesn't always have a chance to respond in time, so that is coming off and should go back on again. What do we have? We have a little over a fair amount of circuitry on that. We've got the transistor to switch the output.

We've got the little chip. Does it have a separate touch sensor? No. The touch sensor may be built into this chip, right? Okay, one moment, please. I'm just going to reverse engineer this.

Okay, let's explore. So this uh chip is marked 2201 I Did not find a dimmer chipmunk that but I Did find one that was identical pinwise and it was called Rh6616 that fits the description perfectly. The circuitry is a bit uh, it's cheating in one area, but it is a fairly standard circuit. Things: Worthy On the of noting a circuit board, lots of stability capacitors you've got the main incoming supplies are capacitor, you've got the reduced power supply via this cheat of a resistor and a Zener diode instead of a regulator.

This capacitor is part of the frequency. The touch sense or I guess might be part of an oscillator. The sense plate itself is another side and is a 1K resistor in the series. If we look at the circuit board we can see oh, hold on, let me pick it up.

It's very small. The large pad there that is connected to that do another. Pads on the other side are one little link from the negative to the transistor and then this output pad is uh, replicated on the other side and coupled through with pleated through holes and that is purely for thermal dissipation from this transistor just to boost the rating a little bit. Um, things worth of note about the chip: these two pins are for programming a mode.

You can determine the operation of the Chip And This pin here is for programming the frequency. It can either be positive or negative and that will determine the pulsive modulation frequency. The modes can vary between the touch to dim up, touch them down, or to step through different intensities and with memory or without. I Don't know if this actually has sustained memory though.

when it's turned I Guess it? Oh, it might. That's when you touch it, it tends to dim out completely. What this might be doing is it might be turning off and then it'll come up to that pre-programmed setting. Um, after that, you've got the uh, pull down resistor for the mosfet and E090, and then the gate resistor for the mosfet and one little LED here that actually is mounted in the back of the board which shines through the front of it to the touch side just purely to mimic the output.

Let me show you the schematic. notably the Zener Diode. It's kind of cheating, but it's cheap. that's why they did it.

Incoming: 5 volt Supply that decoupling capacitor across it. Here is the cheated power supply with a 510 Ohm resistor and a 3.1 or 3.2 volt Zener Diode in a capacitor across it. what that means. Unfortunately is that because that simple voltage drop worth current limiting, it means that in standby without being on at all, this thing instead of having a super low current consumption, is actually going to draw 4 milliamps, which is a bit naughty, but if you plug it into a plug-in while power supply or a power bank, that's not much of an issue since it'll probably just shut itself off anyway if it's a fairly decent one.

The touch input plate has a 1K resistor and that I presume is too limit to if someone touches it and does an electrostatic discharge. That means that the clamp diodes in here will be able to clamp that the output has the resistor to the mosfet and the cooldown resistor to keep mosfet in a known off state for stability and that just pulls the output to zero volts. and also lights that Led which mimics the output. Whatever intensity you've set it for that Led will be the same level of intensity and that is it.

The most notable thing is the two mode pins. You can find a data sheet on this if you look up uh, rh6616 and for a PDF data sheet but it isn't Chinese so you'll have to use translate app and the other pin. There is the frequency of course that sets the Um frequency which is quite high at something like four Kilohertz I think it was, but you can actually it. The frequency will depend on the mode.

It can go very high with just the straight uh, multiple intensity settings where you just choose low, medium, or high and that is it. So the whole set is kind of interesting. The most interesting thing is these lamps and the fact that you know it's drawing about an amp at the five volts. Um, which is pretty good.

It means that you know it'd be perfect using that string. You don't need this circuitry. You could get rid of this and you could just put a switch in the series and you could run it off solar as well. It might be a good verbs off-grid sort of for student lighting.

I Find this quite unusual: this screw in cap that they haven't screwed it and they've actually just crimped it into that base and notice the fact that it's got this little plug-in bit. but they've used the actual glass standoff inside for the actual filaments. probably because it was standard and that loose wobbly wire I Found trapped and the case was literally just one of the filament tills coming off the glass and the other ones get a little resistor spot welded onto it. The 12 ohm resistor.

Quite interesting. Quite an interesting Set of Lights Indeed, I could find many uses for these I Like the fact the whole lot operates effectively at low voltage. it has many uses for that, so quite neat. Interesting: Set of Lights.