# Does the voltage change instantaneously in an inductor?

## Does the voltage change instantaneously in an inductor?

1 From this, we can see that an sudden change in the voltage across a capacitor—however minute—would require infinite current. This isn’t physically possible, so a capacitor’s voltage can’t change instantaneously. An inductor’s current can’t change instantaneously, and inductors oppose changes in current.

## What happens when inductor voltage flips?

When we flip the switch the inductor becomes a current source. With the current continuing in the same direction, the voltage across the inductor flips. Look at the circuit above and see that the positive voltage is at the top of the inductor.

**Why it is not possible for the current in an inductor to change instantaneously?**

Before the switch is closed, there is no voltage or current across either the resistor or the inductor. When the switch is first closed, the current through the inductor is zero, because it cannot change instantaneously. The changing magnetic field creates a back emf which acts to oppose the current in the inductor.

**Does inductance change with voltage?**

The effect of an inductor in a circuit is to oppose changes in current through it by developing a voltage across it proportional to the rate of change of the current.

### Why does current lag in inductor voltage?

In circuits with primarily inductive loads, current lags the voltage. This happens because in an inductive load, it is the induced electromotive force that causes the current to flow. The induced electromotive force is caused by a change in the magnetic flux linking the coils of an inductor.

### Can capacitors jump voltage?

If a capacitor is NOT connected directly to the 0v rail, it will JUMP UP AND DOWN.

**Do inductors increase voltage?**

Inductors react against changes in current by dropping voltage in the polarity necessary to oppose the change. When an inductor is faced with an increasing current, it acts as a load: creating voltage as it absorbs energy (positive on the current entry side and negative on the current exit side, like a resistor).

**Does inductor lead or lag?**

Pure inductive circuit: Inductor current lags inductor voltage by 90°. Current lags voltage by 90° in a pure inductive circuit. Things get even more interesting when we plot the power for this circuit: In a pure inductive circuit, instantaneous power may be positive or negative.

#### Why do capacitors lag voltage?

When the ac voltage(changing voltage) is given across the capacitor it needs time for that signal to pass through that capacitor. That is why the voltage always lags the current in the case of the capacitor.

#### Why do capacitor opposes sudden increase in voltage?

Capacitors resist changes in voltage because it takes time for their voltage to change. The time depends on the size of the capacitor. A larger capacitor will take longer to discharge/charge than a small one. The statement that capacitors resist changes in voltage is a relative thing, and is time dependent.