Ceramic Resistor Heat Sink

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.

Ceramic resistor heat sink.

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

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. However even this description is out of date. Headquarters 27501 bella vista parkway warrenville il 60555 usa 1 866 9 ohmite 1 866 964 6483. It is a nickname for the heat resistant ceramic case in which a coil of resistance wire is potted.

Ohmite s heatsinks provide a low cost thermal solution for these specific packages in multiple sizes. Nowadays the resistance wire itself may be replaced by a moulded spiral of metal oxide compound. A simple practical heat sink is an aluminum or steel plate as shown in figure 1.