The positive feedback is required by an amplifier to act an oscillator. The feedback here means:
- External input is necessary to sustain ac signal in output
- A portion of the output power is returned back to the input
- Feedback can be achieved by LR network
- The base-collector junction must be forward biased
The Correct Option is B
Solution and Explanation
The correct answer is (B): A portion of the output power is returned back to the input
Explanation:
Feedback means a portion of the output power is fed to the inputs.
Positive feedback involves taking a fraction of the output signal and introducing it back into the input, often in phase with the input signal. This can result in a cumulative effect, where the signal keeps reinforcing itself, leading to sustained oscillations.
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Concepts Used:
Oscillations
Oscillation is a process of repeating variations of any quantity or measure from its equilibrium value in time . Another definition of oscillation is a periodic variation of a matter between two values or about its central value.
The term vibration is used to describe the mechanical oscillations of an object. However, oscillations also occur in dynamic systems or more accurately in every field of science. Even our heartbeats also creates oscillations. Meanwhile, objects that move to and fro from its equilibrium position are known as oscillators.
Read More: Simple Harmonic Motion
Oscillation- Examples
The tides in the sea and the movement of a simple pendulum of the clock are some of the most common examples of oscillations. Some of examples of oscillations are vibrations caused by the guitar strings or the other instruments having strings are also and etc. The movements caused by oscillations are known as oscillating movements. For example, oscillating movements in a sine wave or a spring when it moves up and down.
The maximum distance covered while taking oscillations is known as the amplitude. The time taken to complete one cycle is known as the time period of the oscillation. The number of oscillating cycles completed in one second is referred to as the frequency which is the reciprocal of the time period.