Final answer:
Option 1: A choke input filter works on the principle of inductance, which allows inductors to act as high-frequency filters by increasing reactance at high frequencies, thus impeding rapid current changes.
Step-by-step explanation:
The theory on which a choke input filter works is primarily inductance. Choke input filters rely on an inductor's ability to impede changes in current, especially at high frequencies. In AC circuits, when a sinusoidal voltage is applied to an inductor, the voltage leads the current by a 90° phase angle. This characteristic allows inductors to act as high-frequency filters by increasing reactance at high frequencies, which reduces the current and thereby filters out the unwanted high-frequency components. This reactance is directly related to the frequency of the applied signal, meaning that at higher frequencies, the reactance is larger. In the context of AC circuits and filtering, a large inductor can be utilized in series to reduce high-frequency noise in applications such as sound systems or computer power supplies.
A choke input filter works on the principle of inductance. An inductor in an AC circuit reacts differently at different frequencies. At higher frequencies, the reactance of the inductor is large, impeding rapid change and reducing the flow of current. This property of inductors allows them to filter out high frequencies, making them useful in reducing high-frequency sound output or power spikes.