Define dead zone of instrument and explain the reasons of dead zone.
Definition of dead zone: It is the largest range of values of a measured variable to which the instrument does not respond. It is the largest change of input quantity for which there is no output of the instruments. It is basically range of input value for which output is zero. Dead zone is also known as Dead band or dead space or neutral zone.
Reasons of dead zone: Dead zone can be intentional or unintentional. Unintentional dead zone is caused by friction or by permanent set in highly stressed material. Intentionally dead zone is provided to increase the life span of the instrument.