frm prasad
2007-02-04 01:06:27 · 3 answers · asked by bhanu p 1 in Science & Mathematics ➔ Physics
Diodes can be said as 'one way switches'i.e.,they aloow the flow of current only in direction.
2007-02-05 22:56:59 · answer #1 · answered by A Kid Student 3 · 0⤊ 0⤋
A {semiconductor} device which conducts electric current run in one direction only. This is the simplest kind of semiconductor device, it has two terminals and a single PN junction. One diode can be used as a {half-wave rectifier} or four as a {full-wave rectifier
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The fundamental theory behind Diode operation can be expressed by way of the diode current-voltage relationship:
Id = Is( e ^ (Vd/nVt) - 1 )
From this equation we can see that with a large enough forward voltage applied, the diode begins to conduct with magnitude according to the eVd/nVt limiting term. In the reverse situation, we see that the eVd/nVt approaches a very small value and the current can be approximated according to the Is value (which is usually small). This relationship holds true until the point of reverse breakdown is reached, at which time the Diode fails to function according to the fundamental theory. At reverse breakdown voltage the diode will abandon its non-linear behavior and allow for a rapid increase in current versus incremental voltages. The two breakdown mechanisms in semiconductor diodes are Avalanche and Zener breakdowns. Each occurs as a result of different mechanisms coming into play, yet they are oftentimes mistakenly confused. In fact, in many cases both Avalanche and Zener breakdown mechanisms can be observed together in causing this device 'failure'.
2007-02-04 10:27:31 · answer #2 · answered by veerabhadrasarma m 7 · 0⤊ 0⤋
Diode is the two terminal semiconductor device which has unidirectional current property
2007-02-05 05:34:12 · answer #3 · answered by ? 2 · 0⤊ 0⤋