What happens to the energy stored in an inductor when the circuit is disconnected?
1 Answer
When a circuit containing an inductor is disconnected or the power supply is turned off, the energy stored in the inductor does not instantly disappear. Instead, the inductor opposes any sudden change in the current flowing through it, which results in a phenomenon called "inductive kickback" or "inductive back EMF" (Electromotive Force).
Here's what happens to the energy stored in the inductor when the circuit is disconnected:
Sudden current interruption: When the circuit is disconnected or the power supply is turned off, the current through the inductor cannot change instantaneously. So, if there was a steady current flowing through the inductor, it tries to maintain that current.
Inductive kickback: As the current tries to change, the inductor generates an opposing voltage across its terminals to resist this sudden change. This opposing voltage is often referred to as "inductive kickback" or "back EMF."
Voltage spike: The inductive kickback results in a rapid increase in voltage across the inductor. The magnitude of this voltage spike depends on the rate of change of the current (how quickly the current was interrupted) and the inductance of the inductor. The higher the inductance and the faster the current change, the larger the voltage spike.
Protection considerations: If the circuit does not have any protection measures, such as diodes or snubber circuits, to absorb or dampen the inductive kickback, this voltage spike can cause damage to other components in the circuit, particularly sensitive electronic components or switches.
To prevent damage due to inductive kickback, engineers often employ protection methods, such as placing a diode in parallel with the inductor (called a "flyback diode" or "freewheeling diode") to provide a path for the current to flow safely when the circuit is disconnected. This diode allows the energy stored in the inductor to dissipate harmlessly.
In summary, when a circuit with an inductor is disconnected, the energy stored in the inductor manifests as an opposing voltage spike, and appropriate protection measures are necessary to prevent damage to the circuit.
Here's what happens to the energy stored in the inductor when the circuit is disconnected:
Sudden current interruption: When the circuit is disconnected or the power supply is turned off, the current through the inductor cannot change instantaneously. So, if there was a steady current flowing through the inductor, it tries to maintain that current.
Inductive kickback: As the current tries to change, the inductor generates an opposing voltage across its terminals to resist this sudden change. This opposing voltage is often referred to as "inductive kickback" or "back EMF."
Voltage spike: The inductive kickback results in a rapid increase in voltage across the inductor. The magnitude of this voltage spike depends on the rate of change of the current (how quickly the current was interrupted) and the inductance of the inductor. The higher the inductance and the faster the current change, the larger the voltage spike.
Protection considerations: If the circuit does not have any protection measures, such as diodes or snubber circuits, to absorb or dampen the inductive kickback, this voltage spike can cause damage to other components in the circuit, particularly sensitive electronic components or switches.
To prevent damage due to inductive kickback, engineers often employ protection methods, such as placing a diode in parallel with the inductor (called a "flyback diode" or "freewheeling diode") to provide a path for the current to flow safely when the circuit is disconnected. This diode allows the energy stored in the inductor to dissipate harmlessly.
In summary, when a circuit with an inductor is disconnected, the energy stored in the inductor manifests as an opposing voltage spike, and appropriate protection measures are necessary to prevent damage to the circuit.