 Hey there guys, I am well after quite a lot of running around with power supplies and such today I managed to, I managed to sort of kill this again, you know this power supply. Every time I try and get it to give me some power it just kills it, but so anyway I'll forget that for now. I want a little variable power supply, so I built one. This is my power coming in, if I clamp this down it makes a circuit, so I've got AC coming in to my little transformer here. This transformer is connected to my little retroactifier, so you can see that's where the connections are, so I've got one side of the transformer goes to this part of the retroactifier, this one goes to this part here, this junction, and then I come off here and here, and this is going to indicate the positive, indicate the negative, and it's in line with a couple of capacitors. This voltage then comes across here, it's only jumped to here so I can get into it easily. I suppose really I could take some of this out, but it's literally just jumped, this is the negative side which is the white wire here, positive is the yellow, and it's just jumped here so I can get another attachment to ground. From the input pin there, from there, my positive of the power supply goes to the input of the 317, I've got a little resistor here, 510 ohms between the output and the adjust, you can use, you know, 120, 180 or 1k in between on there, and then from the adjust pin to the centre of the pot, and then from the, well facing me it's the left, but if it was facing the other side it'd be the right, I don't even think it matters actually, it will matter because if I turn down it goes down, if I turn up, if I had this the other way around, if I turned up it would go down, if I turned down it would go up, so from here that just goes to ground, and all of them as well, I've just taken off from ground here to another little tiny smoothing capacitor there, I can't know what size that is, it's not very big, oh it's a thousand mic I think, yeah it is, and then I've got my outputs, so that little IC, that's just a little op amp, I'm going to have a little play around with that and see about doing some controlling of that, it's only because I've looked at the red that you can, and this wire here is absolutely nothing to do with it, so I've just got my two outputs then, negative side of the capacitor here, positive side of the capacitor here, and that's going off to the, you can't see that, it's going off to this zero multimeter, come here, I need to tidy up this bench, it wasn't like this earlier one, I've tidied it up twice today, but it's just got as messy again, so that's going to that multimeter, and I've also got this little clock timer kit thing connected, and I have my scope connected, so I just wanted to see how dirty the output was, and that's why I put the capacitor in, because there was a little bit and I've managed to clean it up just by checking that capacitor in, so yeah, pretty chuffed, so here we go then, I'm just going to flick down the power, oh well a natural patch, I thought I'd killed this because I wired it the wrong way around, I wired it the same as what I would do for just the 7809 regulator, which is here, and so I had that in, I thought I'd knackered it, so I kicked it out and put another one on the heatsink and put it in, and it works fine, so I've just checked it, let's just make sure that we're on the right pins, yep, and yeah the one that I thought I'd killed, because it wasn't working, it wasn't performing, let it cool down, and it all fixes again, so yeah, pretty chuffed, so what I'm going to do now then is I'm just going to flick down this, and as you'll see I'm just straight to the reference voltage 1.2, 1.26, and I'm going to turn it up there, and you should see as it comes up, four volts, well we haven't got this connected, I was expecting to see this come on, but if I just plug that in now, it doesn't normally make that noise, probably because it needs a little bit more than three and a half volts to work, and so there we go, let's come on, it's a bit annoying this thing is, because it's got no battery back up, and as soon as you just pull the power, it starts at 10, 10 every time as well, don't really know why, I'm sorry if I keep not seeing the video in the camera, it says I've got it in my hand, but it's the easiest way to see it, so I can use this little adjustment here, let's just see it, it'll go up, but don't turn it too quick, it'll go up, this little clock can only take up 12 volts, and we can turn it back down again, down it goes, and that clock should have gone out, there we go, so the clock's on, now the interesting thing about this is when I take this off, from this little power supply here, the AC comes in, if I use this green one in here, I've got seven volts, if I use this green one in this one, I've got seven volts, if I use these two, I've got 14 volts, and of course when you convert it into DC, you think you'd lose, you've voltage a bit, but no, because watch, I should have 14 volts tops, if I turn this up, oh yeah you think we should be stopping around about now, but oh no, let's just keep going, and there we go, all the way to 17.6 volts, awesome, let's take that back down again, there you go that's, I mean that's, I can't believe how easy that was, that's a real simple little circuit, and it works great, and in a minute I'm going to put another little circuit on it so I can charge a battery there, just for something to do, basically if you didn't have this little AC part here, you literally just have another power supply that you connect onto this, that's simple, the schematic's on the TI website, and it's just really simple to put forward, that's my first variable power supply, because I couldn't get this one to work, cheers watching guys, take care, bye