Although I've looked at plenty of mains voltage lamps, I've not looked at many of the low voltage MR16 style lamps. so let's correct that: let's take a look at one. We'll actually take a look at two, but we'll need to take a look at one because this status one is exactly the same lamp as this twin pack. ultra bright and they're both rated 4.5 watt equal 35 watts and 4.5 watt equal 35 watt.

It is the same lamp so named. MR16 comes from Mr Metalized reflector because they used to be Metalized reflector and 16 8 of an inch in diameter which is 2 inches. There we go two inch diameter lamp. That's what those figures mean.

These are designed for working on AC or DC. Let's start just opening one up, shall we? Let's Zoom down in this: the design for AC are DC and uh, the one thing they're not really suitable for is use with electronic Transformers For Halogen lighting, you can use them in the 12 volt. DC Supply You can use them with a traditional ordinary heavy Transformer that puts out 50 or 60 Hertz, but you cannot use them reliably with the more compact electronic drivers for halogen lamps because those Transformers normally need a decent load. I'm just going to try and get this out.

this may not be successful. I think I'm going to have to open these little tangs. this is a the LED circuit board is pressed onto another circuit board at the back with the driver. Um, but if you use them with the Spider-Man bear for this if you use them with their electronic transfers, they require a minimum load and they can be quite unstable, but even in normal operation, they can.

Well, this is not working actually. But even with normal uh, even if you get the load high enough, it causes problems because those electron Transformers are just going to use violence here. Those electronic Halogen Transformers put at very high frequency Uh pulses and those pulses are often quite high voltage. Okay, right, really ripped out.

So here is the circuit board we're looking for and what I'll do is I'll take a picture of this and then we'll explore it further and I'll explain why the Halogen Transformers can damage these lamps one moment, please. And resume. We'll start with the LED module. The LED module has seven LEDs but they're all in parallel and each one has three chips.

So the voltage of each LED is roughly 9 volts and that makes it a quite easy to drive up. From the 12 volts you just have to drop, use a buck regulator to drop the voltage down and the current regulation. Um, the circuit board with the driver has two capacitors, two inductors on this side, and then a bridge. react for our discrete project far on this side and a control chip.

Now I Could the control chip is not marked and this one I Found a equivalent sort of pin compatible chip. bit of reflection here isn't there El8862 and that does seem to have the same functionality with that being the control pin. So what we have here, we have a current sense resistor for regulation the current through the LEDs. We have the chip itself.

We have the inductor to actually drop the current, and then we have this sort of flyback diode. But there is a mystery component here. It's marked B1 and it said measures are dead. Sure, almost like there's a link in place of something.

I Do not know what this is I Haven't a clue what that component is or what it's for because it's not part of the normal design and it's not like it's been used as a link to jump over a track I Really don't know what B1 is. So the redirect fire is based on the four discrete diodes. They go straight to capacitor. Then there's an inductor with a resistor across it, which I've not drawn.

The schematic: I shall add that in a moment, and then there's another smoothing capacitor so that's just basically providing a bit of filtering and then this then drops the current. There's a couple of tiny little capacitors just I don't even think they're shown in the uh, the schematic. the official schematic. Not sure, but they're just very low volume.

They seem to be sort of for filtering, possibly to protect LEDs against spikes or the to lessen the kick from this inductor. Let me show you the schematic. Let's add that missing component that I've just spotted across the inductor. It's a resistor and it is just basically across the inductor there.

What value was that? The value of that was Five, One two five One and two Zeros Five One Zero Zero Ohms 5.1 k. Foreign: there's the catastrome. Now, this one is rated 25 volts. Note that if you use it with the aforementioned high frequency Electronic Supply That puts out a series of spikes, it may charge up to well above 25 volts potentially 30 volts plus and it may actually damage this capacitor.

It may cause it to fail. It will certainly put stress in it. Also, this sort of pulsing high frequency output may cause problems with the bridge rectifier. Um, but there is the rectified Supply website.

You can use either low frequency AC or you can just use fixed DC or just sort the polarity out itself, smoothing, filtering, more smoothing, and then this chip here, the el8862. If it is that every company seems to clean each other's products, then normally I would expect things like a current sensors to return to the zero volt reel, but in this case it's actually going up to the positive reel. So what happens here is that? Um, the positive rail here? So let's say plus 12 volts roughly and zero volts current. When this turns on, the inductor current can flow through the center resistor 0.24 ohms through the LEDs and there's three LEDs in series effectively.

But then there's a seven multiples of those in parallel. There's a two little tiny capacitors and the current flow shouldn't Doctor but initially because then Doctor has no magnetic field and it starts building up magnetic field and that pushes back a bit against the current so it limits how much current can flow. Um, when that then turns off this inductor, it uh, causes the field in that collapse and whereas this end was going negative and this end was positive, will reverse and it'll find a path through this shot Q Diode. So for greater efficiency, so the LEDs lighten both half of that cycle, there's the mystery B Component I Do not know what that is at all.

If you have any ideas, leave a message down in the comments: Uh, Once at the current, well, the current is set by this Uh 0.24 Ohm resistor as soon as it reaches a specific level that measures the voltage between the positive Rail and this point and that and it sensed there by the feedback. Let's call that feedback and and that basically limits how much current will flow on each cycle of the Uh driving the LEDs. Not sure what the value of these are because. uh, they're quite low value I Couldn't really test them in the circuit I wasn't getting good figures I'd really have to take them out of circuit and have a more accurate meter for that, but that's more or less it can.

you hack these for other uses. Unfortunately, they're very hard to get apart. You always end up bending the iron and plate trying to open these, and that's going to put a lot of stress in the LEDs themselves. But having said that, if you're living off grid, if you're living in a 12 volt system, these will happily handle a wide voltage range.

so pretty much handle from about say the minimum which these LEDs are going to like. say nine or ten volts, which you don't really want your 12 volt battery going below that and it will have to handle up to about 24 volts probably. So it's going to be well within the range of a standard car battery, but that is it. Uh, the Poundland because that's where these came from.

both the status and the ultra bright MR16 12 volt lamps. They're actually really very simple inside and quite nicely laid out. A good logical design.