ABSTRACT
Many electronic systems dissipate a relatively small amount of heat and may not require forced air or liquid flow for cooling. On the other hand, forced air or liquid flows are generated by fans or pumps that are noisy and have shorter life compared to most electronic devices. Therefore, it is better to avoid forced convection cooling in systems that are designed for low maintenance, long life, or low acoustic noise. Examples of these systems are televisions, video cassette recorders (VCRs), compact disk (CD) and digital video disk (DVD) players, personal modems and routers and firewalls, cell phones, handheld computers, portable game consoles, and wireless outdoor base stations and radio units. Heat transfer inside these systems and from their external surfaces to their ambient is partly through natural (free) convection and partly through radiation. These two modes of heat transfer will be studied in this and the next chapter, respectively.
