"RRRR...RRRRRR...RRRRR...RRRRR...RRRR" ??? I know it depends on the interval, but if say, it was turned down to a 7v equivilient?
It depends on that fan, but at 7v equiv, no i shouldn't think so. Only at very slow speeds do they start to make noises and eventually stall.
kk, 120mm panaflo LA1s stall around 6ish though iirc :s i think ill build one and find out tbh, best way before i go build a full bus of em.
Nope, i know sweeeeet FA bout transistors! \o/ me panaflos only kick out 3W last time i checked though.
Them's fones, not fans. A lot depends on the fan and pwm frequency you use. I've a bought Coolermaster ball-bearing one that makes a fast clicking noise and others I've built grumble or growl at low revs. Mounting firmly in a case will help reduce the noise, in fact you may not notice it with a cpu fan whining away in the same system. You can build a nice 3-channel controller with a 25p LM339 quad comparator and 3 20p 2N2222A transistors... my next project.
My case is literally silent, so any obscure noise *will* be heard I'd like to see that 3 channel controller once youve done ive got a 4 fan jobbie designed here.
know the feeling its when u spend 8 hours on a college project then connect the power backwards by accident right at the end thats even worse
Yeah, I spent half a day trying to figure out what was wrong with my circuit, when I had just put the chip in backwards Don't you love electronics
well... it changed the cap round and it worked .. sort of. The fan was massively underpowered and barely turned even though its on a dedicated 12v rail i turned up the pot and it went a tad faster but still it went "vrr...vrr...vrr...vrr...vrr...vrr...vrr...vrr...vrr...vrr..." which is not good. Anyhoo i resoldered in the cap and now it frikkin doesnt work again WTF?! sodding pwm 555.. **** piece of crap
muahahahahahhaaaaa ITS ALIIIIIIIIIIIIIIIIIIIVE OMG the transistor is absolutely scorching hot though think it might burn out perhaps Ok this is just wierd: If i switch it off, the LED dims and the fan goes real slow. But if i switch it on the fan picks up speed and the LED is at full brightness. HOWEVER the pot doesnt do ANYTHING!? there's no change in speed when i adjust it edit: on further inspection rtt told me that my trainsistor was the wrong way round, so i swapped that round and now the fan actually turns off when i switch it off, although the transistor is still burning hot My pot does FA too - its got nowhere near the range it thought it would have. Im gonna whack out the multimeter and see what the true voltage range is. edit: lost my multimeter (could this get any worse?)
Either A) get a better transistor, the biggest usually only handle 2W B) Stick a heat sink on the transistor. Get a bigger pot in there as well if you are having range problems. I could help you more if i had a circuit diagram.
cant stick a heatsink on it - not the right type of package its exactly the same as above ^^ circuit.
You need a high power transistor, TIP121 is allways a safe bet. Lower the 10K base resistor to 1K and increase the VR value, should get mroe range on it then.
ty m8 where do i get a Tip121 from? id rather get it from maplins as i can get it on the way to uni tomorrow morning. edit: nm, ill ask tomorrow morning and see what he's got in stock.
wonderful ur a big help d00d many thx Why when i put in high power npn into the search it comes up with nothing LOL
