FET MALVINO Flashcards
1
Q
- 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
a. Is a voltage-controlled device
2
Q
- 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
A
d. Either one or the other, but
not both
3
Q
- The input impedance of a JFET
a. Approaches zero
b. Approaches one
c. Approaches infinity
d. Is impossible to predict
A
c. Approaches infinity
4
Q
- The gate controls
a. The width of the channel
b. The drain current
c. The gate voltage
d. All of the above
A
d. All of the above
5
Q
- 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
A
b. Reverse biased
6
Q
- Compared to a bipolar junction
transistor, the JFET has a much
higher
a. Voltage gain
b. Input resistance
c. Supply voltage
d. Current
A
b. Input resistance
7
Q
- 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
A
d. Gate-source cutoff voltage
8
Q
- When the drain saturation
current is less than IDSS, a JFET
acts like a
a. Bipolar junction transistor
b. Current source
c. Resistor
d. Battery
A
c. Resistor
9
Q
- RDS equals pinchoff voltage
divided by
a. Drain current
b. Gate current
c. Ideal drain current
d. Drain current for zero gate
voltage
A
d. Drain current for zero gate
voltage
10
Q
- The transconductance curve is
a. Linear
b. Similar to the graph of a
resistor
c. Nonlinear
d. Like a single drain curve
A
c. Nonlinear
11
Q
- The transconductance increases
when the drain current
approaches
a. 0
b. ID(sat)
c. IDSS
d. IS
A
c. IDSS
12
Q
- A CS amplifier has a voltage
gain of
a. gmrd
b. gmrs
c. gmrs/(1 + gmrs)
d. gmrd/(1 + gmrd)
A
a. gmrd
13
Q
- A source follower has a voltage
gain of
a. gmrd
b. gmrs
c. gmrs/(1+ gmrs)
d. gmrd/(1 + gmrd)
A
c. gmrs/(1+ gmrs)
14
Q
- When the input signal is large,
a source follower has
a. A voltage gain of less than 1
b. Some distortion
c. A high input resistance
d. All of these
A
d. All of these
15
Q
- The input signal used with a
JFET analog switch should be
a. Small c. A square wave
b. Large d. Chopped
A
a. Small
16
Q
- A cascode amplifier has the
advantage of
a. Large voltage gain
b. Low input capacitance
c. Low input impedance
d. Higher gm
A
b. Low input capacitance
17
Q
- VHF covers frequencies from
a. 300 kHz to 3 MHz
b. 3 to 30 MHz
c. 30 to 300 MHz
d. 300 MHz to 3 GHz
A
c. 30 to 300 MHz
18
Q
- When a JFET is cut off , the
depletion layers are
a. Far apart
b. Close together
c. Touching
d. Conducting
A
c. Touching
19
Q
- When the gate voltage
becomes more negative in an
n-channel JFET, the channel
between the depletion layers
a. Shrinks
b. Expands
c. Conducts
d. Stops conducting
A
a. Shrinks
20
Q
- If a JFET has IDSS 5 8 mA and
VP 5 4 V, then RDS equals
a. 200 V
b. 320 V
c. 500 ohms
d. 5 kilo ohms
A
c. 500 ohms
21
Q
- 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
c. Gate bias
22
Q
- Self-bias produces
a. Positive feedback
b. Negative feedback
c. Forward feedback
d. Reverse feedback
A
23
Q
- 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
A
24
Q
- Transconductance is measured
in
a. Ohms
b. Amperes
c. Volts
d. Mhos or siemens
A
25
25. Transconductance indicates
how eff ectively the input voltage
controls the
a. Voltage gain
b. Input resistance
c. Supply voltage
d. Output current
