Electronic Devices - Semiconductors - Discussion
Discussion Forum : Semiconductors - General Questions (Q.No. 5)
5.
As the forward current through a silicon diode increases, the internal resistance
Discussion:
28 comments Page 1 of 3.
ROHIT TOMER said:
1 decade ago
FIRST OF ALL EVEN IF diode follows ohm's law than going by definition of ohm's law "R" is a proportionality constant so as V increases I increases keeping are constant. As its a nonlinear device it doesn't follow ohm's law. So the question should be more clear whether he is asking for resistance by depletion layer or parasitic resistance.
S Chakraborty said:
1 decade ago
R is the constant of proportionality . So . we can't say that R will decrease as current increases as per Ohm's Law . Of course R will decrease in this case. In case of diode, the dynamic resistance is related to the current by R=(Thernmal Voltage )/ Current through the diode , at room temp R=(26 mv)/I. Hence the result.
Jay said:
7 years ago
When forward current increase then due to power dissipation some temp increase due to temp more electrons and holes created due to this majority charge carriers increase some amount so so conductivity increase so resistivity decrease resistance decrease.
Neha said:
1 decade ago
R is the constant which has to overcome. The current increases when applied voltage increases, that is, once after overcoming the resistance quantity.
But w.r.t increasing current, the resistance is small not decreasing.
But w.r.t increasing current, the resistance is small not decreasing.
Poonam patel said:
1 decade ago
A real diode has 2 components to the forward resistance. One is the apparent resistance of the PN junction and that decreases with increasing current. The other is a parasitic resistance and it is assumed to be constant.
Vivek said:
1 decade ago
As the current through diode increases heat is dissipated so more electrons in valence band jump to conduction band resulting further increase in current which is clear indication of decrease in resistance.
Mohit said:
9 years ago
Actual reason for this answer.
Semiconductors are having negative temperature coefficient so when current increases due to this temperature also increase and because of this resistance decreases.
Semiconductors are having negative temperature coefficient so when current increases due to this temperature also increase and because of this resistance decreases.
(1)
Vinay said:
6 years ago
but I had a query?
That is in diode internal resistance is nothing but the internal voltage of 0.7(si) and 0.3(ge) which is constant. Then why it is solved by ohm's law?
That is in diode internal resistance is nothing but the internal voltage of 0.7(si) and 0.3(ge) which is constant. Then why it is solved by ohm's law?
Sukhi said:
1 decade ago
As per the diode relation v i.e. voltage across the diode is fix V = IR. If current is increasing that is obviously decreasing the resistance.
Charul sharma said:
1 decade ago
For semiconductor ohm's law is not applicable think another When current flow due to semiconductor electron free so resistance is decrease.
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