 Hey YouTube Sort of show you this this is my little My little circuit for a It says motor there, but it's that's just there for the fan It's a a temperature controlled Fan basically running off a 12 volt 12.7 volt battery, which would be my My batteries from the solar panel We got a 5k NTC native temperature coefficient Pyristor there And then what happens and we got a 500k hot here Which can use as so you use this LM741 as a voltage comparator and so basically when this side is a Highlight this motor doesn't work when it goes low because we tend the Don't know voltage up This side will then go low Actually put it on there. You can see And then we got a we've got a fan action And as it cools back down again between 20 and 25 the motor stops Turn it back up again 25 and off it goes again Now that's all one and good making it in there But for me it's just a it just shows that the circuit works, which is quite good And so I built it down here. I may as well take this off here because it doesn't actually show So I've got it built up here. The only difference is is I haven't got a NTC Pyristor so I've just put another 4.7k Resistor there but You can still turn it on and off and you can you know There is a an area between you gotta just ignore this circuit This is plus I keep this on this fan so I can put it on to other projects that take more than 12 volts And it doesn't blow the fan But yeah So basically just Put that up a little bit turn it down There you go simple Simple little circuit Now I know That this will work here I'm quite happy to order myself some 4.7k NTC I tried doing it with these LM35s But I bought a whole bunch of them I say a bunch of them five of them from China, but none of them worked None of them worked some of them we had to actually put in the reverse way around to actually get it to do anything Otherwise it was just shorting Not very good at all That's a PMP transistor as well. That's the first time I've actually used one You know by itself Rather than having to turn the voltage up then on the base to make this work you're actually gonna Reduce it The rest of the circuit to work So the old learning curve Great fun playing with a simulator though because at least then you get to play around. I've got the I've got the faults and everything switched on on this thing Simulation you see they've got explosions and faults on so if there is any there are any faults I did have some earlier. I kept having apparently sort of like 40 odd amps go through this And it kept blowing out the motor And the diode But I'm not quite sure what was going on there. I need to do some more playing around and And experimenting but that's what it's all about though, isn't it? so I'm quite chuffed that that's a That is gonna be a working system using that 741 I'm gonna end up building up. I just gotta wait for the NTCs and build up a little board I'm hoping I can do it so I can control Over there those two fans one either the side of the batteries So as it gets warmer the fans kicking of course, it's the temperature drops Hands are your Yeah, pretty chuffed that works As you can see it doesn't really take a great little power there rather that's only because it's doing that little fan And it's gonna have two over there in series because the The solar panel will sort of let through sort of about 17 volts maximum so I can just about get away with this This particular 741 because this will let me do 18 volts But I don't know what it'll be like with a varying voltage going up and down on this So I may end up having to use one of these Just to keep a a steady voltage or as close as I can get to a steady voltage probably about 12 volts Maybe a little bit higher In from the in from the solar panel before I guess this I would see Yeah, I'm quite chuffed with that because I need something that works and this this will actually do it or at least it shows here that if I am You know if I go up in the heat my motor starts turning I drop back down in the heat again Especially this is adjusted The motor stops at 25 so above 25 We've got the motor working and we drop it down to 25 again and the motor stops Brilliant. Anyway, cheers watching guys