Heat Sinks Made Easy
The first line of defense in the thermal management of any small electronics is the heat sink. A heat sink is a device that is used to help provide solutions for overheating electronics by keeping them from overheating. Heat sinks work with junctions in order to keep things cool.
Consider, for a moment, the thermal management system of your own computer. The heat sink on your computer is secured to the microprocessor to absorb its heat and dissipate this heat into the air while you work. Generally speaking, the temperature of the microprocessor chip should not exceed 122 F – 131 F (50-55C) at its maximum capacity. In a standard Intel computer, the heat sink is found on the microprocessor’s side, or on top of it for computers that have a ZIF socket. Most heat sinks are secured to the microprocessor with a clip, and thermal grease will act as a seal to absorb heat between the two.
The heat sink will come with the electronics device, and may or may not have a fan. A passive heat sink dissipates heat directly into the environment around it, while an active heat sink has a fan attached, and may be referred to as heat sink/fan (HSF). Thermal resistance is a critical function of heat sinks, and refers to the measure of the element’s ability to dissipate heat efficiently. The best heat sinks then are the ones that have a large surface area that can offer good airflow in order to dissipate heat efficiently.
The heat sink functions through direct contact or proximity with the junction, which, as we mentioned in a previous post, is the hottest point of a processor in an electronic device. The heat that is generated by the energy that is consumed by the processor flows from the junction to the heat sink, which takes the heat and dissipates it into the air. The goal of course is to see a reduction in thermal resistance. Electronics designers today seeking thermal solutions for overheating electronics then need to determine how and when to use heat sinks through calculations of thermal resistance and thermal circuit models with Ohm’s Law.
