Electronics and heat, two things that don’t play well together. You may have noticed that your electronic devices can kick off a fair bit of heat, but have you ever wondered why? And why is heat generation and heat in general a problem for electronics?
The scientific explanation is a simple one: electronic devices are made up of materials like metal and manufactured components such as semiconductors, in which some of the electronics break away from the atoms. When a device is activated, the electromotive force provided by the power source drives the electrons to move, taking information from one component to another, and doing things like taking information from one component to another to produce the images on your phone screen or the audio coming out of your speakers.
When electrons traverse through the metals or semiconductors found in our electronic devices, interactions with the constituent ions of these materials are inescapable. The mean free path, which signifies the average distance an electron covers between successive collisions, is instrumental in understanding the acceleration and energy gain of electrons. When these electrons collide, they transfer the acquired energy from the electric field (E) to the positively charged ions, causing them to oscillate more vigorously, consequently elevating the temperature of the material (manifested as increased kinetic energy of the ions).
These collisions are in fact the reason for the electrical resistance of materials. The greater the number of collisions, the higher the resistivity of the material. To completely mitigate the issue of heating, we would require a material in which electrons move freely without encountering any ion collisions. Such materials are referred to as superconductors, but unfortunately, existing technological constraints make their application in electronics impractical.
So, in broad strokes, you have how heat is generated by electronics, too much heat and components melt or catch fire, as well as generally perform worse at raised temperatures. What can we do to mitigate this heat factor? And is there any way of dissipating it? Short answer: yes! Here’s how:
Heat dissipation in electronics
Thermal-induced damage needs to be avoided at all costs, the main way of doing this is to dissipate it to the surroundings of the electronic device. According to Newton’s law of cooling, the heat dissipation rate is proportional to the temperature difference between the body (electronic device) and the surroundings. So, therefore, the temperature rise in electronics ceases when the heat generated within it equals the heat dissipation to the surroundings. When this is achieved, we say the device has reached thermal equilibrium.
It may sound like thermal equilibrium is the aim of the game here, but the thermal equilibrium temperature of most electronic devices is actually detrimental to their service life and can even cause device failure in electronic systems.
Raising heat dissipation rates in electronics
To make electronic devices thermally safe for operation, the heat dissipation rate needs to be increased to achieve overall lower operating temperatures for the device, thereby going below equilibrium and tipping the scales in our favour. The environmental ambient temperatures around the device is crucial to consider when deliberating heat dissipation strategies. High atmospheric density is an added advantage when considering cooling techniques to lower the device’s operating temperature. It therefore follows that low atmospheric density results in high device operating temperature.
Thermal management technologies play a crucial role in enhancing heat dissipation within electronic devices. An illustrative method involves the integration of a cooling fan within the computer processor unit, enabling forced air cooling as an effective thermal management approach as it forces fast and efficient heat removal. Employing general ventilation practices can significantly reduce device operating temperatures when compared to setups lacking ventilation.
The foremost consideration for improving heat dissipation in electronic devices revolves around providing an ample surface area for heat to dissipate from the device into the surrounding environment. As this surface area expands, the electronic device can effectively shed more heat, leading to lower operational temperatures.
However, it’s essential to acknowledge that surface area-based thermal management techniques might be insufficient when addressing high-power density electronic devices. In these scenarios, an alternative approach entails incorporating heat sinks to achieve an increased heat dissipation rate.
Heat sinks – how they work and how to use them
High-density electronic devices boast smaller dimensions in comparison to their traditional counterparts, a characteristic that can lead to swift and excessive increases in device operating temperatures. As previously mentioned, a strategy for curtailing the operating temperature of high-power-density components involves the deliberate augmentation of their surface area. This is accomplished by affixing heat sinks to these components, facilitating rapid heat dissipation.
Typically, heat sinks are crafted from materials such as copper or aluminium and incorporate fin structures that serve to expand the available surface area, thereby enhancing the efficiency of heat dissipation. The integration of heat sinks with other thermal management techniques, such as forced air cooling or well-ventilated enclosures, can further bolster heat dissipation rates within compact and congested electronic designs.
The importance of effective heat dissipation in high-power-density electronic devices remains paramount. Ongoing innovations in thermal management techniques continue to emerge, aimed at mitigating device operating temperatures. TAD electronics suite of design and analysis tools stands as a valuable resource for designers seeking to implement tailored thermal management strategies for specific electronic devices.
So there you have it! The basics behind heat generation, management and dissipation in electronic devices that manufacturers such as us at TAD electronics employ day to day to improve function for the users. If you’d like to discuss this topic further or find out about more advanced techniques that we can use on a device for you, click here to get in touch. Or continue reading on!