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November 2023 StudentZone Quiz Solution

Question 1:

Why the clipping occurs when the amplitude of the sine wave is increased?

Answer 1:

Clipping occurs when the output signal of the audio amplifier reaches its maximum voltage level, causing it to flatten or "clip" at the maximum value it can handle. The amplifier in this lab activity is designed to operate from a single 5V supply. When the amplitude of the input sine wave is increased beyond the amplifier's capabilities, the output signal tries to reach voltage levels beyond the supply range (greater than 5V or less than 0V). As a result, the output waveform becomes distorted as it gets clipped at the maximum or minimum voltage levels that the amplifier can achieve.

Question 2:

Why there occurs audible feedback when the loudspeaker and the microphone are close to each other?

Answer 2:

Audible feedback occurs when the output sound from the loudspeaker is picked up by the electret microphone, amplified, and then fed back into the loudspeaker again. This forms a feedback loop where the sound keeps building upon itself, resulting in a continuous increase in volume and a high-pitched whining or howling noise. The feedback loop is created when the microphone is close enough to the loudspeaker to pick up the sound it produces and convert it back into an electrical signal, which is then re-amplified and sent to the loudspeaker.