Unit – IV Field Effect Transistor
1. Junction Field Effect Transistor (JFET) contain how many diodes?
a. 4
b. 3
c. 2
d. 1
Answer: 2
2. A “U” shaped, opposite-polarity material built near a JFET-channel center is called the:
a. Gate
b. Block
c. Drain
d. Heat sink
Answer: Gate
3. What is the input impedance of a common-gate configured JFET?
a. Very low
b. Low
c. High
d. Very high
Answer: very low
4. JFET terminal “legs” are connections to the drain, the gate, & the:
a. Channel
b. Source
c. Substrate
d. Cathode
Answer: source
5. With the E-MOSFET, when gate input voltage is zero, drain current is:
a. At saturation
b. Zero
c. IDSS
d. Widening the channel
Answer: zero
6. How will electrons flow through a p-channel JFET?
a. From source to drain
b. From source to gate
c. From drain to gate
d. From drain to source
Answer: from drain to source
7. A JFET is also called ……. Transistor
a. Unipolar
b. Bipolar
c. Unijunction
d. None of the above
Answer: unipolar
8. A MOSFET is sometimes called ……… JFET
a. Many gate
b. Open gate
c. Insulated gate
d. Shorted gate
Answer: insulated gate
9. The pinch-off voltage of a JFET is about ….
a. 5 V
b. 0.6 V
c. 15 V
d. 25 V
Answer: 5 V
10. The gate voltage in a JFET at which drain current becomes zero is called …….. voltage
a. Saturation
b. Pinch-off
c. Active
d. Cut-off
Answer: pinch-off
Unit – V Sensors & Transducers
1. What causes the piezoelectric effect?
a. Heat or dissimilar metals
b. Pressure on a crystal
c. Water running on iron
d. A magnetic field
Answer: pressure on a crystal
2. What type of application would use a photovoltaic cell?
a. An automobile horn
b. A TI 92 calculator
c. A magnetic field detector
d. A remote power source
Answer: a remote power source
3. Change in output of sensor with change in input is
a. Threashold
b. Slew rate
c. Sensitivity
d. None of the above
Answer: sensitivity
4. Inductive proximity sensors can be effective only when the objects are of ……… materials.
a. Ferromagnetic
b. Diamagnetic
c. Paramagnetic
d. All of the above
Answer: ferrormagnetic
5. The linear variable differential transformer transducer is
a. Inductive transducer
b. Non-inductive transducer
c. Capacitive transducer
d. Resistive transducer
Answer: inductive transducer
6. The transducer used for the measurements is/are
a. Resistance temperature detectors
b. Thermistors
c. Ultrasonic
d. All of these
Answer: all of these
7. Function of transducer is to convert
a. Electrical signal into non electrical quantity
b. Non electrical quantity into electrical signal
c. Electrical signal into mechanical quantity
d. All of these
Answer: non electrical quantity into electrical signal
8. Potentiometer transducers are used for the measurement of
a. Pressure
b. Displacement
c. Humidity
d. Both (a) & (b)
Answer: both (a) & (b)
9. Thermistor is a transducer. Its temperature coefficient is
a. Negative
b. Positive
c. Zero
d. None of these
Answer: negative
10. With the increase in the intensity of light, the resistance of a photovoltaic cell
a. Increases
b. Decreases
c. Remains same
d. None of these
Answer: decreases