Final answer:
A non-linear resistor allows surge current from overvoltage to pass to ground, protecting other components in the circuit. They are commonly used in power distribution systems to protect against overvoltage and prevent damage to sensitive components.
Step-by-step explanation:
A non-linear resistor is a type of resistor that does not have a linear relationship between voltage and current. In other words, the current through the resistor does not increase proportionally with the voltage applied across it. Instead, a non-linear resistor allows surge current from overvoltage to pass to ground, protecting other components in the circuit.
For example, in high-current situations, such as when a device with a low resistance is switched on, a large current flows. This can cause a larger voltage drop in the wires and reduce the voltage across other components, like a light bulb, causing it to dim noticeably.
Non-linear resistors are commonly used in power distribution systems to protect against overvoltage and prevent damage to sensitive components. They can be found in devices like surge protectors and circuit breakers.