Computers are a fact of life in the modern workplace or home. They can be purchased for around $1,000, so most people can afford them. As new software is developed, we find that the modern personal computer is a very powerful adjunct to modern living. Unfortunately, computers are digital devices and as such produce EMI. The degree of EMI is indicated by the fact that current computer speeds sound like radar frequencies (450 MHz)! This means that there are RF signals on the inside of computers that must be shielded or filtered. Much of the filtering or shielding will be the same as for other products and so will not be discussed again here. What we will cover in this chapter is special features of computers.