## Transistors and Amplifiers Quiz: Test Your Understanding of Semiconductor Devices and Amplifier Circuits

### 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

(a) base
(b) collector
(c) emitter
(d) case

### 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
Answer: (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
Answer: (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
Answer: (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
Answer: (a) collector current to emitter current

(a) 0.033 mA
(b) 1 mA
(c) 30 mA
(d) unknown

### 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
Answer: (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
Answer: (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

### 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

### 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

### 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

### 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

### 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
Answer: (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
Answer: (a) in phase with the input signal

### In a class A amplifier, the output signal is

(a) distorted
(b) clipped
(c) the same shape as the input
(d) smaller in amplitude than the input
Answer: (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
Answer: (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
Answer: (b) 180° of input cycle

### Feedback oscillators operate on the principle of

(a) signal feedthrough
(b) positive feedback
(c) negative feedback
(d) attenuation

### Which characteristic does not necessarily apply to an op-amp:

(a) high gain
(b) low power
(c) high input resistance
(d) low output resistance

(a) 10 dB
(b) 20 dB
(c) 50 dB
(d) 100 dB

(a) 0.667 V/ms
(b) 1.5 V/ms
(c) 96 V/ms
(d) 0.75 V/ms

(a) 50 mV
(b) 49.5 mV
(c) 495 mV
(d) 500 mV

(a) 0.01
(b) 0.1
(c) 0.0099
(d) 101

(a) 0.0099
(b) 1
(c) 99
(d) 101

(a) Acl ≠ 1
(b) inversion
(c) high Rout
(d) noninversion

(a) -100
(b) -0.01
(c) 100
(d) -250

### If you know an op-amp’s open-loop gain and nothing else, you can determine the closed-loop gain of

(a) an inverting amplifier
(b) a noninverting amplifier
(c) a voltage-follower
(d) none of the amplifier configurations without additional information

### The feedback attenuation of a voltage-follower is

(a) unity
(b) less than unity
(c) greater than unity
(d) variable

### The value of B in a certain noninverting amplifier is 0.025. The closed-loop gain is

(a) unity
(b) 40
(c) 0.025
(d) undeterminable