mean. n. 1. Something having a position, quality, or condition midway between extremes; a medium. 2. A number that typifies a set of numbers, such as a geometric mean or an arithmetic mean.he antilog of the mean of the logarithm of the calculated values, the same as the n th root of the product of the values. It is often a more useful mean for growth curves.
Threshold Voltage Threshold voltage, V, is defined as the minimum gate bias which can form a conducting channel between the source and drain. For power MOSFETs, it is usually measured at the drain-source current of 250uA. Gate oxide thickness and doping concentration of the channel can be used to control the V .
A metal (or poly-crystalline) gate covers the region between source and drain, but is separated from the semiconductor by the gate oxide. The basic structure of an n-type MOSFET and the corresponding circuit symbol are shown in figure 7.1.1. As can be seen on the figure the source and drain regions are identical 1.