This is a strange one unless, of course, you live in singapore because that's apparently where it derives from this is a vehicle sign that you stick in the inside of your windscreen and when you turn it on it, lights up, bright, green and says grab, and it Does appear to be associated with a singaporean food company, so i'm not sure why it was being sold in the uk ebay, but it was - and i bought one because i wanted to see how they laid the circuit board out so i'll turn the light off. So you can actually see this in full intensity. One moment please yeah. Now that is very bright.

I have to say almost glaringly bright. I suppose it's going through the windscreen, so it's not really going to dazzle the driver much but um. I get the feeling you don't really need to this little led indicator in the the button, because uh the thing is bright enough. That you'll know when it's on okay, i'm gon na bring the light back and then we'll explore the circuitry.

The circuitry is very simple in the same way, the led tape typically has three leds and a resistor per section. That's what they've done here. They've put the surface mount resistors on with a pile of resistors at the side, and then the tracks are as follows: they have a common positive track. That goes underneath the bottom of the word, and it goes up to the start of each set of three leds.

The negative appears to be the ground plane of the printed circuit board and the resistors just tap onto that ground plane, except this. For some odd reason i mean the ground plane continues in there, but for some reason they actually ran a specific track for it, but that then goes to the other end of the leds, and then the orange indicates the interconnecting bit. So in this particular instance, they have exactly three multiples each time, and it literally is just the 12 volt supply, three leds, a resistor, a 120 ohm resistor and then going down to the zero volt or the ground um. Just as the sort of like the to complete the circuit very straightforward, there's a few places they've had to get devious with the tracks, particularly, i think this is one of the most complex ones going back from the bottom here or where they've looked across from this Led over to the little stack of two leds over there uh it's neat enough.

It certainly does the job uh. The resistors are 120 ohms. I took some calculations for the current uh, where i've got a note of that. Um 10 volts showed 80 milliamps, 11 volt showed 130 milliamps, that's the whole sign and there are how many sections are there here? One two: three: four: five: six: seven: eight nine ten eleven twelve thirteen sections of three leds, so uh, 10 volts, 80 milliamps, 11 volts under 30.

Milliamps 12 volts is a base voltage of a vehicle battery 173 milliamp, but the charging voltage 13 volts, 225 milliamps and right at the top, the maximum charge voltage of the battery of roughly 14 volts. It's 278 milliamps. And if you work that out on the kink calculator so that uh 13 circuits at 278, milliamps so 278 milliamps divided by the 13 circuits, equals 21 milliamps, so they've basically optimized it for the maximum desirable current on the led tape. They typically have used 150 ohm resistors, but in this instance they're pushing it just a little bit hard because i guess, while the vehicles are active, the voltage of the battery is going to be pretty up much at 14 volts.

But that's it. It's an interesting idea, and it does suggest that if you wanted to make a standard sort of signage thing yourself, then you could do the same thing. It's also interesting to know, apart from this slightly crappy uh screen print here, it's worth mentioning that you can actually see the segment. So the actual outline of this is tracks they've, just laid out as a circuit board, but it's pretty neat the other.

The back of it is just cheap material um. It's just that sort of srbp synthetic resin bonded paper with the two thin wires going through it. Oh, let's check if there's a let's check, if there is a fuse in here, there should be a fuse there usually is. There is a fuse.

What does the fuse rated at three amp, which is more than ample? I do kind of get the urge to open this now. Should i open it? Yes, i should let's zoom down in this and we'll open it up a screwdriver. That's the wrong type of screwdriver find the right screwdriver. Can i find the right screwdriver? Oh, that's.

Definitely wrong screwdriver hold on. There is not going to be anything special in here. It's just going to be probably the led resistor and the little switch on a circuit board or not a little circuit board. So there it is, there's the led.

A little click on click off switch, a little rectangular led, which is odd and then a resistor tucked at the side. What value is the resistor orange orange red? So quite a high value of 3.3 k, but there we go. That is the grab sign. Should you desire one for some inexplicable reason as an ornament in your home,.