An inductor is a coil.

An **inductor** (or reactor) is a passive electrical component that can store energy in a magnetic field created by the electric current passing through it. An **inductor**'s ability to store magnetic energy is measured by its inductance, in units of henries. Typically an **inductor** is a conducting wire shaped as a coil; the loops help to create a strong magnetic field inside the coil due to Ampere's Law. Due to the time-varying magnetic field inside the coil, a voltage is induced, according to Faraday's law of electromagnetic induction, which by Lenz's Law opposes the change in current that created it. Inductors are one of the basic components used in electronics where current and voltage change with time, due to the ability of **inductors** to delay and reshape alternating currents. **Inductors** called chokes are used as parts of filters in power supplies or to block AC signals from passing through a circuit.

**Capacitors and Inductors - Mirror Twins**

Capacitors oppose changes in voltage.

Capacitors store potential energy - energy due to position.

Time constant for capacitor and resistor is CR.

**Inductors** oppose changes in current.
**Inductors** store kinetic energy - energy due to motion.

Time constant for **inductor** and resistor is L/R.

The inductor current increases over time while the capacitor current decreases over time.

The inductor voltage decreases over time while the capacitor voltage increases over time.

The voltage across the **inductor** follows an exponential decay curve but the current in the **inductor** follows an inverse exponential decay curve.

**Inductors** affect the rate of change of current not the magnitude of the current.

Energy is stored in an **inductor** by the creation of a magnetic field. An expanding magnetic field opposes the current that creates it.

A collapsing magnetic field aids the current that creates it.

**Inductors** in a circuit add a property to the circuit which acts much like inertia.

**Inductors** store kinetic energy in an electric circuit using magnetic fields.

**Inductors** can be used to create very large voltages in circuits because of the apparent inertia they provide.

Capacitors can be used to create very large currents in circuits because of the capacity they provide.

Capacitors store potential energy in electric circuits using Electric Fields.

In an **Inductor** the current leads voltage by 90°.

V = L(dt/dt)

Increasing current creates + voltage across inductor.

Decreasing current creates - voltage across inductor.