TUTORIAL 1 SEMICONDUCTOR DIODES student copy

KNL 1053 – ANALOG ELECTRONICS TUTORIAL 1 CHAPTER 1 SEMICONDUCTOR DIODES

No 1

Question Sketch the atomic structure of copper and discuss why it is a good conductor and how its structure is different from that germanium, silicon and gallium arsenide. Answer:

2

Define intrinsic material, covalent bonding and negative temperature coefficient Answer:

Remarks

3

List 3 materials that have a negative temperature coefficient and 3 that have a positive temperature coefficient

4

How much energy in joules is required to move a charge of 6C through a difference in potential of 3V

5

Determine the level of Eg for GaP and ZnS

6

Describe the difference between n-type and p-type semiconductor materials

7

Describe the difference between donor and acceptor

8

Describe the difference between majority and minority carriers

9

Sketch the atomic structure of silicon and insert an impurity of arsenic.

10

Sketch the atomic structure of silicon and insert an impurity of indium.

11

Describe in your own word the process of reverse-bias in semiconductor diode of p-type material.

12

Describe in your own word the process of forward-bias in semiconductor diode of p-type material.

13

Using Shockley’s Equation, determine the diode current at 200C for a silicon diode with Is = 50nA and applied forward bias of 0.6V.

14

Repeat problem 13 for T = 1000C. Assume that Is = increase to 5.0µA.

15

Using Shockley’s Equation, determine the diode current at 200C for a silicon diode with Is = 0.1µA at a reverse bias potential of -10V.

16

Determine ac resistance at a current of 1mA and 15mA for the diode of figure below. Modify the equation as necessary for low levels of diode current. (Use rd = 26mV/ID)

17

Referring to Figure below, determine the transition capacitance at reverse-bias potentials of -25V and -10V. What is the ratio of the change in capacitance to the change in voltage.

18

Sketch the waveform for i of the network of Figure below if tt = 2ts, and the total reverse recovery time is 9ns.

19

At what temperature will the 10V Zener diode of Figure below have a nominal volatge of 10.75V.

20

What is the percentage increase in relative efficiency of the device of figure below if peak current is increased from 5mA to 10m?