Does the wattage rating of the resistor matter? I was looking at one store's resistors (33K and 4K3) and they came in 1/2W 1/4W 1/8W. Also, where can I get the MIC29302BT other than RS Components?
The resistors don't carry much current as they only set the reference voltage so 1/4W will be fine. I used the MC29152 chip instead - it's a pin for pin replacement but can only supply upto 1.5A instead of 3A (but thats at least 4 average 8cm fans). I purchased from Rapid electronics - UK based I'm afraid, but the IC cost about £2.50 to give you a guide. Must say though, the circuit works perfectly. I get constantly variable voltage from about 5.5V to 12V over my 3 case fans, system temp at mo is 30 degrees and its as quiet as a mouse at 5.5V, drops to about 25 degrees but sounds like a hurricane at 12V! Cheers
Try Newark in Canada. Code: 83F5919 MICREL SEMICONDUTOR,INC High current low dropout regulator, 26 volt maximum input voltage, adjustable output voltage, 370 millivolt dropout voltage, 3 ampere output current, 5 lead, TO-220, base generic part number MIC29300 Each $5.60 1093 in stock I used the MIC29152 as well for this controller, it's a lot cheaper than the 3A MIC29302 and a straight swap.
