# What will happen if a capacitor is replaced with an inductor?

### Table of Contents

- What will happen if a capacitor is replaced with an inductor?
- Do capacitors and inductors do the same thing?
- Can a capacitor be an inductor?
- Why LC circuits are not possible?
- What happens to a capacitor at high frequency?
- Why use an inductor instead of a capacitor?
- Does a capacitor change voltage?
- Can a capacitor have no inductor current?
- When do inductor voltage and capacitor currents change?
- What happens to the inductor when the switch is closed?
- Can a capacitor be replaced in a DC steady state circuit?

### What will happen if a capacitor is replaced with an inductor?

Replacing the capacitor with an inductor would **defeat the purpose of phase shifting and make the magnetic field to be pulsating**; rendering the IM non-rotational. In single phase induction motor without capacitor the net starting torque in one direction is zero.

### Do capacitors and inductors do the same thing?

A capacitor stores energy in an electric field; **an inductor stores energy in a magnetic field**. ... If a capacitive circuit is disconnected from a power supply, the capacitor will temporarily maintain voltage. If an inductive circuit is disconnected from a power supply, the inductor will temporarily maintain current.

### Can a capacitor be an inductor?

So a capacitor on the input side presents as a **pure inductor** (extremely high Q) on the output side. ICs use such circuit for imitating inductors in their circuits.

### Why LC circuits are not possible?

However, there is a large current circulating between the capacitor and inductor. In principle, this circulating current is infinite, but in reality is **limited by resistance in the circuit**, particularly resistance in the inductor windings. Since total current is minimal, in this state the total impedance is maximal.

### What happens to a capacitor at high frequency?

As the frequency increases, **the capacitor passes more charge across the plates in a given time** resulting in a greater current flow through the capacitor appearing as if the internal impedance of the capacitor has decreased.

### Why use an inductor instead of a capacitor?

Capacitors preserve voltage by storing energy in an electric field, whereas inductors **preserve current by storing energy in a magnetic field**. One result of this is that while capacitors conduct best at higher frequencies, inductors conduct best at lower frequencies.

### Does a capacitor change voltage?

More generally, **capacitors oppose changes in voltage**—they tend to “want” their voltage to change “slowly”. - v i v = L di dt . An inductor's current can't change instantaneously, and inductors oppose changes in current.

### Can a capacitor have no inductor current?

That's not correct. As the capacitor charges, the current through the inductor must increase and this inductor current means that the capacitor voltage can never reach 10V (that would require zero inductor current). This could shown by solving for the step response of the capacitor voltage which is beyond the scope of the question.

### When do inductor voltage and capacitor currents change?

At the instant the switch is opened, the current through the resistor changes instantly from zero to the initial inductor current. In physical circuits, voltages and currents cannot instantaneously change but depending on the characteristic time scale, they can effectively change instantaneously. I = C*dv/dt.

### What happens to the inductor when the switch is closed?

Now when the switch is closed for a long time inductor is now a short-circuit with 0.2 A flowing in it and the resistor, and there is no voltage across the capacitor. So your book is correct about the current in the inductor and wrong about the voltage across the capacitor. Hope this helps.

### Can a capacitor be replaced in a DC steady state circuit?

and so, since the capacitor voltage is constant, the current through the capacitor is zero. This why you can replace the capacitor with an open-circuit. In this case, it follows that both the capacitor current and voltage are zero in DC steady state.