Gerd morning all today. I'm taking a look at this Ven lab AC detector which tells you whether the little tip here which is insulated is in the presence of live main. So let's switch it on, press and hold the red button. uh no.

Mains currently. So let's go and get some mains. Here is some Live Mains this is uh, straight out of a socket in my house that's neutral on the left, that's live on the right. so let's see what this does.

and if we get near to the live, it's showing the orange light and the slow beep which means you're near Mains but not very near it. and if I get right in there I get the red light and the fast beep which means we're very near Mains I Would imagine the manual would tell us how close there is a sensitivity uh button so I can turn that on and it's high sensitivity now. Oh, that doesn't seem to make a huge amount of difference, but anyway, that's designed to make it a little bit more sensitive so that you get an indication when you're a little bit further away. let's just turn that off.

Yes, we do have to get nearer with the Uh unit set in low sensitivity. so here's an example of where it might be useful. uh, poking around inside a distribution box or what we call a consumer unit. So up here, got, um, live there and neutral down here.

that's the live bus bar if I get near that. it definitely uh pointed out as being live and in areas where there isn't live, It beeps slowly. I Mean, there's live all over this box but it would give you the confidence I can't switch this off at the moment because um, this is the solar input. It's quite sunny today, so I've got quite a bit of solar.

so I don't want to really switch it off. Um, yeah, it just gives you the confidence to know that, um, what you're working on isn't live. So what else is there on here? Well, there's a little white LED flashlight. Press that button and we get a little pool of White Light Press and hold this button and bizarrely, you get a red laser dot.

Not entirely sure why you would need a red laser dot. Um, when you're looking for live electrical Mains don't quite understand that, but it's there nonetheless. You can have any combination of white LED and red laser dot. Okay, I think it's time to take this apart? Well, I can start actually by undoing the battery compartment cap and it's two AAA alkalines in there.

The rear part of the unit is held together by this pocket clip there so you can see that starting to come apart. But there's also a screw in here so we'll take that out and that should enable me to open the uh case of this unit. And yeah, there it is. And these side panels come out the side panels which can be branded and there's the printed circuit board, right? this printed circuit board, is, um, can't slide that way because it's up against this plastic molding.

but this hook can't be taken off because it's slightly bent back over the end, which I assume is the connection into the cap when you screw the cap on, thus connecting the batteries. Um, so I think I need to lift this slightly and then yes and that releases that end of the PCB Okay, let's see if I can get that out right. The next thing that needs to be done is this: uh, end cap has to come off. so let's slide that out of there.

Okay, that's out and that's liberated the printed circuit board. Or we can see the little blob chip there. uh, the pads for the three switches which are in here and the connection there. Well, there's the buzzer connection there for the laser module which is in the top there, and then the white LED is down the bottom that shines through that hole there which might also be a lens and then the detector probe sits up inside this transparent plastic tip.

There's not a lot of Point pulling that off because I'm just going to work these laser connections loose. But let's take a look at the circuitry on the underside of the board. Right on here. We've got lots of LEDs Um, this one.

it looks greeny yellow, but I think it's white. Um, there's a sort of white phosphor on there that lights up the on symbol which is the power symbol there. Then we've got um D2 and D3 which I think are orange and red respectively for the high and low um detecting of AC. Then we've also got these two LEDs here which are up on their end and they've got these domed lenses on top.

So I think that's designed to shine through into this front area and I think they're just duplicates of the orange and red LEDs which are designed to shine through the front so that you can see them. Um, when you're not specifically looking at the indicator panel, white led to illuminate your work area is here. Laser is fitted there and soldered onto the board. and the buzzer is here.

Now there's a transistor here. j3 It could be a mosfet that's going to be to switch on and off. possibly the laser. Um, where are the loads of connections? They're there.

Oh, where are they? They're there so that that positive runs back to that point there. and where's that? I can't see exactly, but um, you would need some sort of switch to turn the laser on and off. The LED may not be. you may not need a transistor switch you.

Maybe they'll drive that directly from the chip. Another LED down here. D4 That's going to be for the high low sensitivity which I think is that middle button? Yeah, high and low actually illuminates that middle button? when you're in high sensitivity. A couple more transistors down here.

We'll get some numbers off those in a moment. A blob chip here and lots of resistors and capacitors and that is about it. So it says Ncv here. that's non-contact uh, voltage.

so non-contact voltage measuring or detecting that has a track running all around there. What's that? That's the buzzer and all along here and along here and possibly goes into the chip at that point possibly goes through that capacitor. Um I Can't be completely sure, but uh yeah, the connection for the non-contact voltage tip is quite long, isn't it? All of these transistors are marked J3y so they are Npn transistors. Um, 8050 style transistors or 8050 numbering.

Um, this one here. We can see that this connection down on the bottom here runs up through this little resistor into that pad and that pad appears to pull the negative of the laser down to ground. When this transistor is turned on, these two transistors are going to be. well, one of them probably for the buzzer and the other one perhaps for the white.

LED although I would imagine that's not using much more current than these onboard. LEDs What else could be using current other than the laser, the LED and the buzzer? Not really anything. so I Think we'll assume that these are laser LED and buzzer or something along those lines. Just a couple of things up at the far end here.

we've got a date 2022, 0112 so 12th of Jan possibly. or they might be a weak number perhaps. And also here we've got a five pin connector, which might be programming header for the chip that's under here. It's almost certainly going to be just a microcontroller of some sort.

Um, yes, that doesn't look like there's much Electronics specifically intended to do the non-con contact voltage testing. It probably just comes in, maybe goes through a capacitor straight into the micro and then some software to detect, uh, the inevitable induced if it's induction, or just the signal getting through somehow to that microcontroller. So that's what's inside one of these um, AC detector units. What's it called? Well, this one is the Vd200 Ac voltage detector, then lab branded.

Um, that's what's inside now. I Just got to try and get this. uh PCB back in. that little tongue sits over the end of there.

Hmm, oh yeah, it's just a case of slightly sliding the PCB out that way, getting that hooked over the end, letting the PCB slide back and that all looks like it's in place, right? Let's put the cover back on. Yeah, it's very handy if you're doing uh, electrical work and you just want to be absolutely sure that there isn't any live Mains on whatever it is you're working on, particularly if you're in a distribution box or something like that. I've also got a similar one. It doesn't have the laser.

This is a Parkside branded one. Oddly, the batteries go in the other way on this one. That's a bit strange on this. The positive sticks out the back.

There's the positive goes in the front, but essentially they do the same job. Very useful so you don't electrocute yourself. Cheerio.