Advanced electronic components are featured by miniaturization with lightweight, thin-film, short-length, and small size.
Furthermore, functionally, they are featured by low voltage,
low power loss, high speed, etc. This is heavily indebted to the
development of semiconductor devices. To operate normally
electronic system, the semiconductor devices very susceptible
to transient overvoltage should be protected under any situation. One of many countermeasures for transient overvoltage is
to use a varistor.