Package size and power relationship:
0201 1/20W
0402 1/16W
0603 1/10W
0805 1/8W
1206 1 /4W
Correspondence between package size and package
0402=1.0mmx0.5mm
0603=1.6mmx0.8mm
0805=2.0mmx1.2mm
1206=3.2mmx1.6mm
1210=3.2 mmx2.5mm
1812=4.5mmx3.2mm
2225=5.6mmx6.5mm
The power of a chip resistor is the power generated due to the Joule heat resistance when passing current. It can be calculated according to Joule's law: P=I2 R.
Power rating : It is the maximum permissible power at a certain temperature, and usually refers to the power rating when the ambient temperature is 70°C.
The power rating of a chip resistor is the maximum allowable power at a certain temperature.
Rated voltage : The rated voltage can be found from the following formula.
Rated Voltage (V) = √
Rated Power (W) x Nominal Resistance (Ω)
Maximum Operating Voltage : The maximum voltage allowed to be loaded on both sides of the chip resistor.
The relationship between chip resistor package and power and voltage is shown in the following table: