Questions on Characteristic Curves - the silicon semiconductor diode
Q1.
(a) Sketch the characteristic of a silicon semiconductor diode for forward bias and reverse bias. Indicate approximate values on the voltage axis.
![](D1.png)
forward bias: zero current at origin
rising gradually
sharp increase at just before 0.7 V
reverse bias: zero at origin then slightly less than zero current ![](../../../../graphics/symbols/nuclides/ticksmall.png)
(4 marks)
(b) Describe, with reference to the characteristic you have drawn, how the resistance of the diode changes with the voltage across the diode.
forward bias: The diaode has a high resistance if the potential difference across it is less than 0.7 V
this is why only a small current passes through it.
At 0.7 V resistance decreases rapidly
this results in a rapidly increasing current.
reverse bias: The diode has a very high resistance
therefore very little current is conducted through it.
(3 marks)
(Total 7 marks)
![](../../../../graphics/buttons/Clickhereforsolution.png)