Chapter 17 (Transistors and Applications)

In a common-emitter amplifier, the output ac signal will normally: a) have greater voltage than the input b) have greater power than the input c) be inverted d) have all of the above

d) have all of the above

The Thevenin circuit shown has a load line that crosses the y-axis at: a) +10 V b) +5 V c) 2 mA d) the origin

c) 2 mA

In a common-collector amplifier, the output ac signal will normally: a) have greater voltage than the input b) have greater power than the input c) be inverted d) have all of the above

b) have greater power than the input

The type of amplifier shown with the load resistor in the emitter is a: a) common-collector b) common-emitter c) common-drain d) none of the above

a) common-collector

A major advantage of FET amplifiers over BJT amplifiers is that generally they have: a) higher gain b) greater linearity c) higher input resistance d) all of the above

c) higher input resistance

A type of field effect transistor that can operate in either depletion or enhancement mode is an: a) D-MOSFET b) E-MOSFET c) JFET d) none of the above

a) D-MOSFET

For a FET, transconductance is the ratio of: a) drain voltage to drain current b) gate-source voltage to drain current c) gate-source current to drain voltage d) drain current to gate-source voltage

d) drain current to gate-source voltage

The transistor circuit shown with voltage divider bias on the gate is a(n): a) D-MOSFET with voltage-divider bias b) E-MOSFET with voltage-divider bias c) D-MOSFET with self-bias d) E-MOSFET with self bias

b) E-MOSFET with voltage-divider bias

A Colpitts or Hartley oscillator both have: a) positive feedback b) amplification c) a closed loop gain of 1 d) all of the above

d) all of the above

If you were troubleshooting a JFET circuit, you would expect the gate voltage to be: a) more positive than the drain voltage b) more positive than the source voltage c) equal to zero volts d) equal to +VDD

b) more positive than the source voltage

In a bipolar transistor, if the base-emitter junction is reverse-biased, the transistor will be cutoff.

True

When a transistor is saturated, an increase in base current is not possible.

False

A load line is drawn between saturation and cutoff.

True

The power gain of a CC amplifier is the same as the current gain.

True

A class B amplifier is more efficient than a class A amplifier.

True

A JFET is always operated with the gate-source junction forward-biased.

False

The drain current when the gate-to-source voltage is zero is called IGSS.

False

The transconductance of a FET is the ratio of ac drain current to gate-to-source voltage.

True

A CD amplifier has a current gain less than 1.

False

The input to a feedback oscillator is only the power supply voltage.

True

The n-type regions in an npn bipolar junction transistor are: a) collector and base b) collector and emitter c) base and emitter d) collector, base, and emitter

b) collector and emitter

The n-region in a pnp transistor is the: a) base b) collector c) emitter d) case

a) base

For normal operation of an npn transistor, the base must be: a) disconnected b) negative with respect to the emitter c) positive with respect to the emitter d) positive with respect to the collector

c) positive with respect to the emitter

The three currents in a BJT are: a) forward, reverse, and neutral b) drain, source, and gate c) alpha, beta, and sigma d) base, emitter, and collector

d) base, emitter, and collector

Beta (β) is the ratio of: a) collector current to emitter current b) collector current to base current c) emitter current to base current d) output voltage to input voltage

b) collector current to base current

Alpha (α) is the ratio of: a) collector current to emitter current b) collector current to base current c) emitter current to base current d) output voltage to input voltage

a) collector current to emitter current

If the beta of a certain transistor operating in the linear region is 30 and the base current is 1.0 mA, the collector current is: a) 0.033 mA b) 1.0 mA c) 30 mA d) unknown

c) 30 mA

If the base current of a transistor operating in the linear region increases: a) the collector current increases and the emitter current decreases b) the collector current decreases and the emitter current decreases c) the collector current increases and the emitter current does not change d) the collector current increases and the emitter current increases

d) the collector current increases and the emitter current increases

When an n-channel JFET is biased for conduction, the gate is: a) positive with respect to the source b) negative with respect to the source c) positive with respect to the drain d) at the same voltage as the drain

b) negative with respect to the source

When the gate-to-source voltage of an n-channel JFET is increased, the drain current: a) decreases b) increases c) stays constant d) becomes zero

a) decreases

When a negative gate-to-source voltage is applied to an n-channel MOSFET, it operates in the: a) cutoff state b) saturated state c) enhancement mode d) depletion mode

d) depletion mode

In a common-emitter (CE) amplifier, the capacitor from emitter to ground is called the: a) coupling capacitor b) decoupling capacitor c) bypass capacitor d) tuning capacitor

c) bypass capacitor

If the capacitor from emitter to ground in a CE amplifier is removed, the voltage gain: a) increases b) decreases c) is not affected d) becomes erratic

b) decreases

When the collector resistor in a CE amplifier is increased in value, the voltage gain: a) increases b) decreases c) is not affected d) becomes erratic

a) increases

The input resistance of a CE amplifier is affected by: a) α and re b) β and re c) RC and re d) RE, re, and β

d) RE, re, and β

The output signal of a CE amplifier is always: a) in phase with the input signal b) out of phase with the input signal c) larger than the input signal d) equal to the input signal

b) out of phase with the input signal

The output signal of a common-collector amplifier is always: a) in phase with the input signal b) out of phase with the input signal c) larger than the input signal d) exactly equal to the input signal

a) in phase with the input signal

The largest theoretical voltage gain obtainable with a CC amplifier is: a) 100 b) 10 c) 1.0 d) dependent on β

c) 1.0

In a class A amplifier, the output signal is: a) distorted b) clipped c) the same shape as the input d) pulsed

c) the same shape as the input

A class A amplifier conducts for: a) 90° of input cycle b) 180° of input cycle c) 270° of input cycle d) 360° of input cycle

d) 360° of input cycle

A class B amplifier conducts for: a) 90° of input cycle b) 180° of input cycle c) 270° of input cycle d) 360° of input cycle

b) 180° of input cycle

Feedback oscillators operate on the principle of: a) signal feedthrough b) positive feedback c) negative feedback d) attenuation

b) positive feedback