What does 'back emf' refer to in electrical terms?

'Back emf' refers to the induced voltage that opposes the applied voltage in an electrical circuit. This phenomenon occurs when a magnetic field within a motor (or similar device) experiences a change due to its motion or the motion of nearby magnetic fields. As the current flows through the motor, it generates a magnetic field, and any change in the current generates a voltage that opposes the original current flow. This induced voltage is crucial because it helps to regulate the amount of current flowing through the circuit, especially in electric motors, where it helps to prevent excessive current that could cause overheating and damage.

Understanding 'back emf' is essential for anyone working with electric motors or other inductive devices, as it plays a significant role in the efficiency and performance of these systems. In practical terms, a high back emf at higher speeds means less current is drawn from the power source, aiding in the overall conservation of energy within the system. This can lead to better operational efficiency and longer equipment lifespan.