 Hey YouTube, I always had a little think in my head and I just wondered if I built two identical regulator circuits here, this is a LM338, these are identical circuits and I wondered if having these two identical circuits, if they were powered by two independent supplies or let's say a dual secondary of a transformer, so this is hypothetical I'm thinking it will work, if I have a transformer like that one there and it has two outputs yeah and I let's say just for example I put one side, one secondary here 12 volts, one secondary here 12 volts, can I have using two LM338 a dual rail power supply, so if I attach the output of this one positive rail to the negative output of this one and tap off that and then connect multimeter to the tap and then and the negative and the multimeter to the tap and the positive will I have a dual rail supply, well because you know that once you made I built the circuit up and I just tested it but I did notice I made the video first I did notice I thought that was a bit strange at 1.7 volts here and 1.4 volts here, what's wrong and I just noticed actually that I've put in a LM317 on this side, now this still worked okay but I put an LM317 there and the LM338 there so I've just changed this for an LM338, I'm not even trying it yet but I'm pretty confident that it'll work but that goes to show that you can actually mix these because it did work there's 1.7 volts there like I said in 1.4 volts there so and I can imagine because of the same pin out pretty identical LM350, LM338 and LM317, the difference with 317 of course is you can have a bigger voltage differential but it works so let me just power on both sides of this, flip these, he says it works but on one side we haven't got any power which is here as you can see on the multimeter there's nothing so let me just do a quick check see what I've done wrong that was really simple when I moved took out the LM317, pulling the LM338 I just had it moved over one so we had no power going so I put the arm to that and you can see I was still at 1.7 volts that's a bit strange on one point it's got 5 volts over here let's turn it up slightly it's not but we still have a negative we got a positive voltage there 1.5 volts and we got a negative voltage there minus 1.7 and so I can turn up the negative side to 2.5 volts of course that side still stays the same let's turn it up so you can have as long as you've got two separate supplies you can create a dual rail supply from those two separate supplies and that's powering up with that one there, this one here which is just running off the CTX thinking me wrong this is as far as I've got with testing this I don't know what it's going to end up being or you ended up doing with it but that is that is not too bad if you keep in mind that if you add a transformer with two secondries on it and you did the same thing you could basically make yourself a little dual rail power supply and using an M3 3.8 or M3 1.7 or M3 50s I'm going to presume that you can do the same thing with all of them and if you can't I'll certainly leave it in the comments I feel I'm not going to bother doing too long a video on this or anything I'm just and this little circuit here is basically off the data sheet okay just get off the data sheet there's nothing special about the circuit and all I've done is made two identical ones they're on separate boards they're electrically separated from each other apart from when I hook up from the output negative side here to the output of here this side to make that sense tap that's it I thought that was quite interesting just watching guys and carry on playing around with this for a little while