What is meant by the term "back EMF"?

The term "back EMF" refers specifically to the voltage generated in opposition to the applied electromotive force (EMF) in a circuit, particularly in devices such as motors or inductive components. When current flows through an inductor or coil, it generates a magnetic field. If the current is then interrupted or changed, the collapsing magnetic field induces a voltage in the opposite direction to the change in current, which is known as back EMF.

This opposing voltage serves to hinder the change in the current that produced it, effectively acting as a counter voltage to the applied EMF. This phenomenon is crucial in the operation of electric motors, as it ensures that the device does not draw excessive current and allows for smooth operation. Understanding back EMF is essential for grasping how inductive components behave in response to changes in current and how they impact overall circuit design and performance.