Resistor Wattage

Sourav Gupta's picture


Joined: Feb 12, 2018

Replies: 318
Resistor Wattage
July 27, 2020 - 5:40pm

Suppose I am soldering a 0.25W SMD resistor in a metal clad board, or in a PCB with adequate heatsink. Does the wattage of the resistor gets changed then? If yes what is the relation between the changes? Any professional way to calculate the heat dissipation in such way?

Debashis Das's picture


Joined: Dec 02, 2019

Replies: 98

I have found this ON Semi reference by googling it. And after a quick read, I think this docoument might be helpful to you.

The document is named: A Quick PCB Thermal Calculation for Power Electronic Devices with Exposed Pad Packages​, you can google this up to get it.


jaksonlee's picture


Joined: Nov 07, 2019

Replies: 122

The Resistor Power Rating is sometimes called the Resistors Wattage Rating and is defined as the amount of heat that a resistive element can dissipate for an indefinite period of time without degrading its performance.The power rating of resistors can vary a lot from less than one tenth of a watt to many hundreds of watts depending upon its size, construction and ambient operating temperature.