Amplifier Circuit Concepts and Effects

This video tutorial explains the design and function of a multi-stage transistor audio amplifier circuit. It covers the use of capacitors to block DC and allow AC signals, the role of resistors in controlling input voltage and reducing distortion, and the impact of bypass capacitors on voltage gain. The tutorial also discusses enhancing current and voltage gain in the second stage and the use of transformers to improve efficiency and power gain.

What is the primary function of coupling capacitors in a transistor amplifier circuit?

• To block DC signals and allow AC signals

• To block AC signals

• To reduce the input voltage

• To increase the voltage gain

Why are potential meters used in the amplifier circuit?

• To bypass the emitter resistance

• To adjust the input voltage and prevent distortion

• To increase the frequency response

• To increase the current gain

What is the significance of the beta value in a transistor circuit?

• It is the ratio of collector current to base current

• It determines the voltage gain

• It is used to calculate the impedance

• It controls the input voltage

How do bypass capacitors affect the voltage gain of a circuit?

• They stabilize the voltage gain

• They increase the voltage gain

• They have no effect on voltage gain

• They decrease the voltage gain

What is the purpose of using a transformer in the second stage of the amplifier?

• To reduce the current gain

• To block high frequency signals

• To improve efficiency and increase output voltage

• To decrease the voltage gain

How does a transformer affect the frequency response of the amplifier?

• It favors high frequency signals

• It reduces all frequencies equally

• It has no effect on frequency response

• It favors low frequency signals

What is the maximum theoretical efficiency of a class A amplifier?

• 100%

• 75%

• 25%

• 50%

How is the overall voltage gain of a multi-stage amplifier calculated?

• By subtracting the voltage gains of each stage

• By dividing the voltage gains of each stage

• By multiplying the voltage gains of each stage

• By adding the voltage gains of each stage

What is the effect of using a step-up transformer in the amplifier circuit?

• It decreases both voltage and current

• It decreases the output voltage

• It increases the output voltage and decreases the current

• It increases both voltage and current

What is the role of a capacitor added between the ground and the collector of the transistor?

• To increase high frequency signals

• To increase the current gain

• To filter out high frequency signals

• To filter out low frequency signals