Diode Theory

Question 1

Draw a Diode Curve

Answer 1

Question 2

What is the Knee Voltage

Answer 2

The region at which the current starts to increase rapidly. The knee voltage is the barrier potential.

Question 3

What is the bulk resistance of a diode?

Answer 3

The sum of the ohmic resistances of a diode

Question 4

What is “maximum forward current” of a diode?

Answer 4

The maximum forward current rating for the diode

Question 5

What is the “power rating” of a diode?

Answer 5

The maxmimum power that the diode can safely dissipate without shortening its life. Usually relates to its size - surface area to dissipate heat.

Question 6

Draw the first (ideal) approximation of a diode

Answer 6

Question 7

Draw the second approximation of a diode curve and the equivalent circuit

Answer 7

Accounts for the barrier potential of the diode

Question 8

Draw the third approximation of a diode and equivalent circuit

Answer 8

Accounts for the bulk resistance of the diode

Question 9

How do you get the bulk resistance from data sheets?

Answer 9

V=IR so its the slope V/I

Question 10

What is the operating point when you plot the diode curve and the I vs V of a circuit load?

Answer 10

The intersection point.

Question 11

What are two types of diodes….

Answer 11

Surface Mount (SM) (yellow band)

Small Outline Transistor (SOT) (yellot dot)