Quote: Originally Posted by essenbe
John, don't I remember you buying some Noctua fans? If so, they came with resistors you don't really use, or at least don't need.
No I didn't buy any Steve but my son has one that he didn't fit when he did his build so I guess I can take a look at that.
By the by I tested a 1 watt 39 ohm resistor on the Coolermaster fan (0.6A) and it ran perfectly until it burnt my fingers
sobbing aside LOL!! it appears that it would take a 39 ohm resistor at least at 5 watts (and wirewound) to absorb that amount of energy so there must be a trick in using those small resistors one sees in those speed adaptor cables like this one 4-Pin Fan Speed/Noise Reduction Cable
although I do see that the resistor actually sits in the 5v rail wire whereas I was running that "hot" one in the 12v connector.
The only other solution is to use some of that bar heater wire that glows red when the heater is switched as it is made from a special wire that has an inbuilt resistance per metre.
It is made from an alloy of nickel and chromium - usually and because of the resistance is worked out (the length of the winding) to be at a certain value it gets hot to a point where you get heat for warming the room or making toast in a toaster (same principle) etc etc without actually melting Resistance wire - Wikipedia, the free encyclopedia
I am not sure of what the resistance used to be but it would take a lot of it to make a resistor up for what I need. But I did years ago make ballast resistors for the old points / coil types of car ignition circuits by winding old heater wire onto round mica core and then bury it in heat resistant ceramic cement in a ceramic moulded heatsink and then measure the resistance off as I went so getting the right value for that resistor - see pic for idea of what I mean bit I digress.... .
I'll go look for that Noctua fan again before i get carried away LOL!!