Question

What is positive feedback in a transistor oscillator?

Answer 1

Hint:Positive feedback (also known as aggravating feedback or self-reinforcing feedback) is a feedback loop mechanism that amplifies the consequences of a minor disruption. That is, one of the impacts of a perturbation on a system is for the size of the perturbation to grow. For example, A increases the amount of B, which increases the amount of A. Negative feedback is a system in which the effects of a change operate to diminish or negate it. In science and engineering, such as biology, chemistry, and cybernetics, both ideas are crucial.

Complete answer:
If tank (or oscillatory) and feedback circuits are correctly coupled to a transistor, it may be used as an oscillator to produce continuous undamped oscillations of any desired frequency.All oscillators, regardless of their name, perform the same function: they provide continuous undamped output. They differ, however, in terms of how they provide energy to the tank or oscillatory circuit to compensate for losses and frequency ranges.

The frequency spectrum of oscillators used to generate sinusoidal signals is quite broad (ranging from less than 1 Hz to several GHz). The feedback network in this circuit consists of an inductor and a capacitor, and the feedback is achieved by inductive coupling from one coil winding to another coil. Because the coils are wrapped to the same core, mutual inductance is used to inductively link them.

The base-emitter junction is forward biased, while the base-collector junction is reverse biased in this configuration. The use of positive feedback in the operation of an oscillator promotes an output frequency without the need of any input. Positive feedback increases the output signal by charging a faster and higher signal in the input direction.

Note:The use of a portion of a transistor oscillator's output voltage to adjust its performance is known as feedback. Positive feedback occurs when the feedback voltage is in phase with the input, allowing the feedback to improve the input. Negative feedback decreases the input by 180 degrees out of phase with the input voltage.