Module 6 1

Question 1

What are voltage-controlled devices characterized by?

Answer 1

Higher input impedance

Voltage-controlled devices are less sensitive to temperature variations.

Question 2

What are current-controlled devices characterized by?

Answer 2

Lower impedance

Current-controlled devices are more sensitive.

Question 3

What type of device is a FET?

Answer 3

Unipolar device

FETs are smaller and easily integrated into chips.

Question 4

What type of device is a BJT?

Answer 4

Bipolar device

BJTs are generally bigger integrated circuits (ICs).

Question 5

What are the two main types of FET?

Answer 5

• JFET (Junction FET)
• MOSFET (Metal-Oxide-Semiconductor FET)

Other types include MESFET and variants like D-MOSFET and E-MOSFET.

Question 6

What are the two types of JFET?

Answer 6

• n-channel
• p-channel

n-channel is more widely used.

Question 7

What happens to the depletion region in the cutoff region of a JFET?

Answer 7

The depletion region thickness increases as Vgs becomes more negative.

This occurs until the depletion regions touch each other.

Question 8

What is Idss in a JFET?

Answer 8

Drain current with gate shorted to source

It is a key parameter for JFET behavior.

Question 9

What occurs in the breakdown region of a JFET?

Answer 9

Id increases to an excessive value

This happens if Vds exceeds the avalanche breakdown voltage.

Question 10

What is the function of the gate in a MOSFET?

Answer 10

Controls the width of the channel

The channel allows charge carriers to flow from source to drain.

Question 11

What distinguishes enhancement type MOSFET from depletion type MOSFET?

Answer 11

Enhancement type has no channel initially; it is induced by applying voltage.

Depletion type has a permanently fabricated channel.

Question 12

What are the main characteristic parameters of JFET?

Answer 12

• Mutual conductance or transconductance
• Drain resistance
• Drain conductance
• Amplification factor

These parameters are crucial for understanding JFET operation.

Question 13

True or False: The JFET operates in a linear region where it behaves like an ordinary resistor.

Answer 13

True

This is referred to as the ohmic region.

Question 14

Fill in the blank: The equation of drain characteristics for JFET resembles the equation of a _______.

Answer 14

parabola

This relationship is described by Shockley’s equation.