Resistor Squeaks When Cooling Down
A 4_watt resistor likely needs force_air cooling, or mounting on a metal panel to remove the heat.
Depending on the leads, soldered onto PCB boards, is not the path to reliable systems.
How do we know this?
The thermal resistance of PCB traces, of standard 1.4 mil thickness from the standard 1 ounce of copper foil per square foot, is 70 degree Centigrade per watt per SQUARE OF FOIL.
Thus a path of size 0.020&quot; by 1&quot; (having 50 squares of foil) on each lead of a 2_watt resistor, with 50 * 70 = 3,500 degree Centigrade (temperature gradient) per lead, given the 2 leads producing 1,750 degree Centrigrade temperature rise,
has the RESISTOR self_cooling only by RADIATING
You can do better than that.