Malvino Chapter 13 MCQ With Answers Electronics ECE Board Exam

Malvino Chapter 13 MCQ With Answers Electronics ECE Board Exam




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
a. Is a voltage-controlled device

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
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
c. Approaches infinity

4. The gate controls

a. The width of the channel
b. The drain current
c. The proportional pinchoff voltage
d. All the above
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
b. Reverse-biased
6. Compared to a bipolar transistor, the JFET has a much higher

a. Voltage gain
b. Input resistance
c. Supply voltage
d. Current
b. Input resistance

7. The pinchoff voltage has the same magnitude as the

a. Gate voltage
b. Drain-source voltage
c. Gate-source voltage
d. Gate-source cutoff 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
c. Resistor

9. RDS equals pinchoff voltage divided by the

a. Drain current
b. Gate current
c. Ideal drain current
d. Drain current for zero gate voltage
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
c. Nonlinear

11. The transconductance increases when the drain current approaches

 a. 0
 b. ID(sat)
 c.  IDSS
 d. IS
c.  IDSS

12. A CS amplifier has a voltage gain of

  a. gmrd
  b. gmrs
  c. gmrs/(l + gmrs)
   d. gmrd/(l + gmrd)
a. gmrd

13. A source follower has a voltage gain of

  a. gmrd
  b. gmrs
  c. gmrs/(l + gmrs)
  d. gmrd/(l + gmrd)
c. gmrs/(l + gmrs)



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
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
a. Small

16. A cascode amplifier has the advantage of

a. Large voltage gain
b. Low input capacitance
c. Low input impedance
d. Higher gm
b. Low input capacitance

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
c. 30 to 300 MHz

18. When a JFET is cut off, the depletion layers are

 a. Far apart
 b. Close together
 c. Touching
 d. Conducting
c. Touching

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
a. Shrinks

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                
a. 200 ohm   
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
a. Voltage-divider bias




22. Self-bias produces

 a. Positive feedback
 b. Negative feedback
 c. Forward feedback
 d. Reverse feedback
b. Negative 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
b. Source resistor
24. Transconductance is measured in

 a. Ohms
 b. Amperes
 c. Volts
 d. Mhos or Siemens
d. Mhos

25. Transconductance indicates how effectively the input voltage controls the

 a. Voltage gain
 b. Input resistance
 c. Supply voltage
 d.  Output current
d.  Output current

1 comment:

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