Chapter 14

Chapter 14

39 Maths Exercise Solutions

 and have same lattice structure. Why is  insulator while  and  intrinsic semiconductors?

Question No.1
 and have same lattice structure. Why is  insulator while  and  intrinsic semiconductors?

Suppose a pure crystal has   It is doped by ppm concentration of pentavalent (As). Calculate the number of electron and holes. Given that . 

Question No.2
Suppose a pure crystal has   It is doped by ppm concentration of pentavalent (As). Calculate the number of electron and holes. Given that . 

Can we take one slab of p-type semiconductor and physically join it to another n-type semiconductor to get p-n junction?

Question No.3
Can we take one slab of p-type semiconductor and physically join it to another n-type semiconductor to get p-n junction?

The  characteristic of a silicon diode is shown in the figure. Calculate the resistance of the diode at  and


Question No.4
The  characteristic of a silicon diode is shown in the figure. Calculate the resistance of the diode at  and


In a Zener regulated power supply a Zener diode with  is used for regulation. The load current is to be  and the unregulated input is . What should be the value of series resistor  

Question No.5
In a Zener regulated power supply a Zener diode with  is used for regulation. The load current is to be  and the unregulated input is . What should be the value of series resistor  

The current in the forward bias is known to be more  than the current in the reverse bias  What is the reason then to operate the photodiodes in reverse bias?

Question No.6
The current in the forward bias is known to be more  than the current in the reverse bias  What is the reason then to operate the photodiodes in reverse bias?

Why are and  are preferred materials for solar cells?

Question No.7
Why are and  are preferred materials for solar cells?

From the output characteristics shown in figure. Calculate the values of  and  of the transistor when  is  and


Question No.8
From the output characteristics shown in figure. Calculate the values of  and  of the transistor when  is  and


In figure , the   supply can be varied from to . The Si transistor has  and  Assume that when the transistor is saturated,  and  Calculate the minimum base current, for which the transistor will reach saturation. Hence, determine , when the transistor is switched on.


Question No.9
In figure , the   supply can be varied from to . The Si transistor has  and  Assume that when the transistor is saturated,  and  Calculate the minimum base current, for which the transistor will reach saturation. Hence, determine , when the transistor is switched on.


In figure , the   V to . The Si transistor has  and  Assume that when the transistor is saturated,  and  Find the ranges of  for which the transistor is 'switched off and 'switched on'.


Question No.10
In figure , the   V to . The Si transistor has  and  Assume that when the transistor is saturated,  and  Find the ranges of  for which the transistor is 'switched off and 'switched on'.