Novice question here. How hot are you comfortable running resistors? I am building Rod Coleman's Raw DC boards for his new V-9 regulators. I've determined that the two 0.47Ω resistors are running 105C - 110C. I've also tried two 0.22Ω in series and while cooler they still get pretty toasty. I'm using 7W WireWound Resistors that have a max temperature rating of 350C but I'm wondering if I should get a couple of the aluminum chassis mount style and bolt them to the aluminum chassis rather than have all that heat cooking the inside of the chassis and the boards?
Chassis Mount Resistors
Chassis Mount Resistors
How many watts are the resistors dissipating? Anything that hot I would definitely do as you suggested and move off board.
I'm fan of Welwyn W2x series (it's one of the most robust industrial wirewound resistors), but W22 is a bit weak as R.C. bias resistor.
If you read datasheet, even at 1.5W the rising of temperature (over the ambient temp) reaches 100C.
I usually use W24 or MRA12 resistors there.
The voltage on resistor -about- 1V, so the dissipation on 0.47R is 2.13W (at about 2.13A).
If you read datasheet, even at 1.5W the rising of temperature (over the ambient temp) reaches 100C.
I usually use W24 or MRA12 resistors there.
The voltage on resistor -about- 1V, so the dissipation on 0.47R is 2.13W (at about 2.13A).