(i) Forward current: It is the current flowing through a forward biased diode. Every diode has a maximum value of forward current which it can safely carry. If this value is exceeded, the diode may be destroyed due to excessive heat. For this reason, the manufacturers‘ data sheet specifies the maximum forward current that a diode can handle safely.
(ii) Peak inverse voltage: It is the maximum reverse voltage that a diode can withstand without destroying the junction.
- If the reverse voltage across a diode exceeds this value, the reverse current increases sharply and breaks down the junction due to excessive heat. Peak inverse voltage is extremely important when diode is used as a rectifier. In rectifier service, it has to be ensured that reverse voltage across the diode does not exceed its PIV during the negative half-cycle of input a.c. voltage. As a matter of fact, PIV consideration is generally the deciding factor in diode rectifier circuits. The peak inverse voltage may be between 10V and 10 kV depending upon the type of diode.
(iii) Reverse current or leakage current: It is the current that flows through a reverse biased diode. This current is due to the minority carriers. Under normal operating voltages, the reverse current is quite small. Its value is extremely small (< 1µ A) for silicon diodes but it is appreciable (˜100 µA) for germanium diodes.
- It may be noted that the reverse current is usually very small as compared with forward current. For example, the forward current for a typical diode might range upto 100 mA while the reverse current might be only a few µA - a ratio of many thousands between forward and reverse currents.
Wilfykil answered the question on August 14, 2019 at 09:17
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