MODULE 08-INTRODUCTION TO AMPLIFIERS CH1

What is the (a) input impedance and (b) output impedance of a common-base transistor configuration?

(a) Low (b) high

What are the (a) inputs and (b) outputs of a phase splitter? 1. (a) Two signals in phase (b) One signal 2. (a) Two signals out of phase (b) One signal 3. (a) One signal (b) Two signals in phase 4. (a) One signal (b) Two signals out of phase

(a) One signal (b) Two signals out of phase

What type of coupling is most useful for impedance matching? 1. RC 2. Resistor 3. Impedance 4. Transformer

. Transformer

Which of the following terms describe the two types of feedback? 1. Positive and negative 2. Degenerative and regenerative 3. Both 1 and 2 above 4. Bypassed and unbypassed

1. Positive and negative 2. Degenerative and regenerative

AUDIO AMP = 15Hz - 20KHz

AUDIO AMP = 15Hz - 20KHz

The control of an output signal by an input signal resulting in the output signal having some (or all) of the characteristics of the input signal is known by which of the following terms? 1. Multiplication 2. Magnification 3. Amplification 4. Addition

Amplification

The speaker system of a record player should be driven by which of the following types of amplifier? 1. An audio power amplifier 2. A video voltage amplifier 3. A direct-current voltage amplifier 4. An alternating-current rf amplifier

An audio power amplifier

The signal from a radio antenna should be amplified by which of the following types of amplifier? 1. An rf voltage amplifier 2. A video power amplifier 3. A direct-current audio amplifier 4. An alternating-current power amplifier

An rf voltage amplifier

What type of feedback is provided by a capacitor connected across the emitter resistor in a common-emitter transistor amplifier? 1. Bypassed 2. Positive 3. Negative 4. Unbypassed

Bypassed

What transistor configuration should be used to match a high output impedance to a low input impedance? 1. Common collector 2. Common emitter 3. Common gate 4. Common base

CB = LOW INPUT / HIGH OUTPUT *Common collector = High INPUT / LOW OUTPUT *CE = MEDIUM INPUT / MED OUTPUT

What class of operation has the highest fidelity? 1. A 2. C 3. AB 4. AC

Class A

Class AB = operates at 51-99% of input signal - poor fidelity Class A = 100% of input signal - good fidelity

Class AB = operates at 51-99% of input signal - poor fidelity Class A = 100% of input signal - good fidelity

Class B = operates for 50% of the input signal Class C = most efficient operates at less than 50% of input signal

Class B = operates for 50% of the input signal Class C = most efficient operates at less than 50% of input signal

If the output of a circuit should be a representation of less than one-half of the input signal, what class of operation should be used? 1. A 2. C 3. AB 4. AC

Class C

To provide good fidelity output signals, which of the following classes of operation CANNOT be used by a push pull amplifier?

Class C

What class of operation is the most efficient? 1. A 2. C 3. AB 4. AC

Class C

Most amplifiers can be classified in which of the following ways? 1. Function and size 2. Power requirements and size 3. Function and frequency response 4. Frequency response and power requirements

Function and frequency response

For maximum current at the input to a circuit, what should the relationship of the input impedance be to the output impedance of the previous stage?

Higher than

Which of the following types of coupling is most effective at high frequencies? 1. RC 2. Resistor 3. Impedance 4. Direct

Impedance

What type feedback is provided if the feedback signal is out of phase with the input signal? 1. Unbypassed 2. Bypassed 3. Negative 4. Positive

Negative = DEGENERATIVE

A single-stage, two transistor amplifier that uses a phase splitter input is classified as what type of amplifier? 1. Inverse 2. Push-pull 3. Phase splitter 4. Regenerative

Phase splitter

Distortion caused by amplifier saturation can be reduced by using which of the following types of feedback? 1. Positive 2. Negative 3. Regenerative 4. Unbypassed

Positive

What type of feedback provides an increased amplitude output signal? 1. Positive 2. Negative 3. Bypassed 4. Unbypassed

Positive

What is the most common form of coupling? 1. RC 2. Resistor 3. Impedance 4. Transformer

RC

Which of the following types of amplifiers have both high and low frequency response limitations? 1. RC 2. Resistor 3. Impedance 4. Transformer

RC

RF AMP = 10 kHZ -100,000 MHZ

RF AMP = 10 kHZ -100,000 MHZ

Which of the following is NOT a method of coupling amplifier stages? 1. RC 2. Resistor 3. Impedance 4. Transformer

Resistor

The class of operation of an amplifier is determined by which of the following factors? 1. The gain of the stage 2. The efficiency of the amplifier 3. The amount of time (in relation to the input signal) that current flows in the output circuit 4. The amount of current (in relation to the input-signal current) that flows in the output circuit

The amount of time (in relation to the input signal) that current flows in the output circuit

What is feedback? 1. The control of a circuit output signal by the input signal 2. The control of a circuit input signal by the output signal 3. The coupling of a portion of the output signal to the input of the circuit 4. The coupling of a portion of the input signal to the output of the circuit

The coupling of a portion of the output signal to the input of the circuit

Which of the following is a common use for a push-pull amplifier?

The final stage in an audio amplifier

Which of the following statements describes the relationship of input and output signals in an amplifier? 1. The input signal is actually changed into the output signal 2. Both the input and output signal are unchanged; neither is affected by the other 3. The input signal is controlled by the output signal and the output signal remains unchanged 4. The input signal remains unchanged and the output signal is controlled by the input signal

The input signal remains unchanged and the output signal is controlled by the input signal

For maximum power transfer between circuits, what impedance relationship should there be between the two circuits?

The output impedance of circuit number one should be equal to the input impedance of circuit number two

Why are amplifiers used in electronic devices? 1. To provide signals of usable amplitude 2. To "pick up" broadcast signals 3. To select the proper broadcast signal 4. To change the broadcast signal to an audio signal

To provide signals of usable amplitude

What is the purpose of an amplifier coupling network? 1. To "block" d.c. 2. To provide gain between stages 3. To separate one stage from another 4. To transfer energy from one stage to another

To transfer energy from one stage to another

Which of the following types of coupling is usually used to couple the output from a power amplifier? 1. RC 2. Resistor 3. Impedance 4. Transformer

Transformer

VIDEO AMP = 10Hz - 6MHz

VIDEO AMP = 10Hz - 6MHz