widening of the depletion region. This widening of the depletion region will establish too great a barrier for the majority carriers to overcome, effectively reducing the majority car rier flow to zero, as shown in Fig. 1.13a The number of minority carriers, however, entering the depletion region will not change resulting in minority-carrier flow vectors of the same magnitude indicated in Fig. 1.12c with no applied voltage. The current that exists under reverse-bias conditions is called the reverse saturation current and is represented by Ir. The reverse saturation current is seldom more than a few microamperes and typically in nA, except for high-power devices. The term saturation comes from the fact that it reaches its maximum level quickly and does not change significantly with increases in the reverse-bias potential, as shown on the diode characteristics of Fig. 1.15 for VD e reverse-biased conditions are depicted in Fig. 1.13b for the diode symbol and p-njunction. Note, in particu lar, that the direction of Isis against the arrow ofthe symbol. Note also that the negative side of the applied voltage is connected to the p-type material and the positive side to the n-type ma- terial, the difference in underlined letters for each region revealing a reverse-bias condition.