In an RL (resistor-inductor) circuit, when the current is interrupted suddenly, several key phenomena occur due to the nature of inductors:
Inductor's Opposition to Change: An inductor resists changes in current flow through it. When the current is interrupted suddenly, the inductor generates an opposing electromotive force (EMF) to try to keep the current flowing. This phenomenon is described by Faraday's law of electromagnetic induction.
Inductive Kick: As the inductor generates the opposing EMF, it creates a voltage spike across its terminals. This voltage spike is often referred to as the "inductive kick." The magnitude of the inductive kick depends on the rate of change of current interruption and the inductance of the coil.
High Voltage Spike: The inductive kick can result in a very high voltage spike, potentially causing damage to the circuit or connected components. The magnitude of this voltage spike is proportional to the rate of change of current interruption and the inductance of the coil. Without proper protection, sensitive electronic components can be destroyed due to the sudden surge in voltage.
Sparking: In some cases, if the circuit is not properly designed to handle the sudden interruption of current, sparking can occur at the switch or the point where the current is interrupted. This can lead to arcing and further damage the components or even create a fire hazard.
To prevent the harmful effects of sudden current interruption in an RL circuit, various protection methods are employed, such as using flyback diodes (freewheeling diodes) or snubber circuits. These components help to dissipate the energy stored in the inductor safely, reducing the voltage spike and preventing damage to the circuit. Proper circuit design and the selection of appropriate components are essential to ensure the reliability and safety of the RL circuit when dealing with sudden current interruptions.