Malvino Chapter 13

Chapter 13 
1. A JFET 
a. Is a voltage-controlled device 
b. Is a current-controlled device 
c. Has a low input resistance 
d. Has a very large voltage gain 

2. A unipolar transistor uses 
a. Both free electrons and holes 
b. Only free electrons 
c. Only holes 
d. Either one or the other, but not both 

3. The input impedance of a JFET 
a. Approaches zero 
b. Approaches one 
c. Approaches infinity 
d. Is impossible to predict 

4. The gate controls 
a. The width of the channel 
b. The drain current 
c. The proportional pinchoff voltage 
d. All the above 

5. The gate-source diode of a JFET should be 
a. Forward-biased 
b. Reverse-biased 
c. Either forward- or reverse-biased 
d. None of the above 

6. Compared to a bipolar transistor, the JFET has a much higher 
a. Voltage gain 
b. Input resistance 
c. Supply voltage 
d. Current 

7. The pinch-off voltage has the same magnitude as the 
a. Gate voltage 
b. Drain-source voltage 
c. Gate-source voltage 
d. Gate-source cutoff voltage 

8. When the drain saturation current is less than IDSS, a JFET acts like a 
a. Bipolar transistor 
b. Current source 
c. Resistor 
d. Battery 

9. RDS equals pinch-off voltage divided by the 
a. Drain current 
b. Gate current 
c. Ideal drain current 
d. Drain current for zero gate voltage 

10. The transconductance curve is 
a. Linear 
b. Similar to the graph of a resistor 
c. Nonlinear 
d. Like a single drain curve 

11. The transconductance increases when the drain current approaches 
a. 0 
b. ID(sat) 
c. IDSS 
d. IS 

12. A CS amplifier has a voltage gain of 
a. gmrd 
b. gmrs 
c. gmrs/(l + gmrs) 
d. gmrd/(l + gmrd) 

13. A source follower has a voltage gain of 
a. gmrd 
b. gmrs 
c. gmrs/(l + gmrs) 
d. gmrd/(l + gmrd) 

14. When the input signal is large, a source follower has 
a. A voltage gain of less than one 
b. A small distortion 
c. A high input resistance 
d. All of these 

15. The input signal used with a JFET analog switch should be 
a. Small 
b. Large 
c. A square wave 
d. Chopped 

16. A cascode amplifier has the advantage of 
a. Large voltage gain 
b. Low input capacitance 
c. Low input impedance 
d. Higher gm 

17. VHF stands for frequencies from 
a. 300 kHz to 3 MHz 
b. 3 to 30 MHz 
c. 30 to 300 MHz 
d. 300 MHz to 3 GHz 

18. When a JFET is cut off, the depletion layers are 
a. Far apart 
b. Close together 
c. Touching 
d. Conducting 

19. When the gate voltage becomes more negative in an n-channel JFET, the channel between the depletion layers 
a. Shrinks 
b. Expand 
c. Conduct 
d. Stop conducting 

20. If a JFET has IDSS = 10 mA and VP = 2 V, then RDS equals 
a. 200 ohm 
b. 400 ohm 
c. 1 kohm   
d. 5 kohm 

21. The easiest way to bias a JFET in the ohmic region is with 
a. Voltage-divider bias 
b. Self-bias 
c. Gate bias 
d. Source bias 

22. Self-bias produces 
a. Positive feedback 
b. Negative feedback 
c. Forward feedback 
d. Reverse feedback 

23. To get a negative gate-source voltage in a self-biased JFET circuit, you  must have a 
a. Voltage divider 
b. Source resistor 
c. Ground 
d. Negative gate supply voltage 

24. Transconductance is measured in 
a. Ohms 
b. Amperes 
c. Volts 
d. Mhos or Siemens 

25. Transconductance indicates how effectively the input voltage controls the 
a. Voltage gain 
b. Input resistance 
c. Supply voltage 
d. Output current




Also try:

Malvino Chapter 1
Malvino Chapter 2
Malvino Chapter 3
Malvino Chapter 4
Malvino Chapter 5
Malvino Chapter 6
Malvino Chapter 7
Malvino Chapter 8
Malvino Chapter 9
Malvino Chapter 10
Malvino Chapter 11
Malvino Chapter 12
Malvino Chapter 14
Malvino Chapter 15
Malvino Chapter 16
Malvino Chapter 17
Malvino Chapter 18
Malvino Chapter 19
Malvino Chapter 20
Malvino Chapter 21
Malvino Chapter 22
Malvino Chapter 23
Malvino Chapter 24