Ceramic Resistor Heat Sink

Large wirewound resistors may be rated for 1 000 watts or more.

Ceramic resistor heat sink. Additionally you may want to ensure that the resistor is mounted with an air gap below it as well not touching the pcb to promote air circulation on all sides. Ohmite now carries a line of heatsink solutions that are specifically designed for your bga and pbga applications. Ohmite s heatsinks provide a low cost thermal solution for these specific packages in multiple sizes. A surface mount power resistor with a pad for heatsink may require a copper pour heatsink or a physical heat sink of some kind attached see the datasheet for the component in question.

A simple practical heat sink is an aluminum or steel plate as shown in figure 1. However even this description is out of date. It is a nickname for the heat resistant ceramic case in which a coil of resistance wire is potted. The aluminum cased types are designed to be attached to a heat sink to dissipate the heat.

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 rated power is dependent on being used with a suitable heat sink e g a 50 w power rated resistor overheats at a fraction of the power dissipation if not used with a heat sink. Nowadays the resistance wire itself may be replaced by a moulded spiral of metal oxide compound.