What electronic component is often used to prevent large voltage spikes from being produced when the current flow through an inductor is suddenly terminated?
The correct answer and explanation is :
The electronic component used to prevent large voltage spikes when the current flow through an inductor is suddenly terminated is a flyback diode (also known as a freewheeling diode, snubber diode, or clamping diode).
Explanation:
Inductors store energy in their magnetic fields when current flows through them. According to Lenz’s Law, an inductor opposes any sudden changes in current. When the current through an inductor is abruptly interrupted (such as when a switch or transistor turns off in a circuit), the collapsing magnetic field causes a rapid increase in voltage across the inductor’s terminals. This can lead to dangerously high voltage spikes, potentially damaging circuit components like transistors, relays, or MOSFETs.
A flyback diode is placed in parallel with the inductor (but in reverse polarity) to provide a path for the current when the main current source is suddenly cut off. Instead of allowing the voltage to spike, the diode conducts, allowing the inductor’s stored energy to dissipate safely as current circulates through the diode and inductor. This process effectively prevents excessive voltage buildup.
Applications:
- Relay Circuits: When a relay coil is de-energized, a flyback diode prevents arcing at the switch contacts.
- Motor Drivers: In H-bridge circuits for DC motors, flyback diodes protect transistors from voltage spikes.
- Switching Power Supplies: Flyback diodes help inductor-based power converters operate efficiently.
Characteristics:
- Usually a Schottky diode or fast-recovery diode is used for high-speed applications.
- Common choices include 1N4007 for general applications or 1N5819 for fast switching.
By using a flyback diode, engineers ensure circuit reliability and longevity by mitigating the damaging effects of inductive voltage spikes.