Contents
Do resistors need a heat sink?
No, they do not need a heatsink, as long as the maximum dissipation times the thermal impedance from element to ambient is below the maximum element temperature.
Do resistors need cooling?
Much smaller than standard parts of the same wattage, Heatsinkable resistors release their heat in one plane. Once the heat is absorbed it is released into the air through the heatsink. Although much smaller, they require the use of a heatsink to achieve the wattage advertised.
Why does the resistor get hot?
Overheating of Resistor When a resistor is placed under a voltage that approaches the upper limits of its power rating, the resistor generates more heat than normal. This is due to the voltage attempting to force more current (electrons) through the resistor than it is designed to pass.
What kind of heat sink should I use for this 50W resistor?
When trying to calculate what kind of heat sink I need it seems my values don’t make sense. So let’s assume 30 degrees ambient, 40 watts of power. The resistor is rated at 1.9K/W, I’ll be using thermal paste rated at 0.11K/W, and then I need a heat sink which is the unknown in the equation.
What happens when a resistor is attached to a heat sink?
When a resistor is attached directly to the heat sink, the heat generated by the resistor conducts to the metal plate, and then into the air as a result of convection. The cooling ability of the metal plate depends to a certain extent on whether the metal plate is oriented vertically or horizontally because of natural convective air cooling.
How is the thermal resistance of a heat sink determined?
Thus, if the thermal resistance of the heat sink and the ambient temperature are determined, the maximum power which can be applied to the resistor without exceeding its maximum operating temperature can be determined.
What is the purpose of a heat sink?
The purpose of the heat sink is to draw heat from the small resistor element (thus keeping the temperature of the element below its maximum operating temperature) and then dissipating the heat by conduction and convection over the much larger area of the heat sink. A simple, practical heat sink is an aluminum or steel plate as shown in Figure 1.