How do surge protectors work to prevent damage?

Surge protectors work by limiting the voltage supplied to an electrical device by blocking or shorting any unwanted voltages above a safe threshold.

Surge protectors, also known as surge suppressors, are devices designed to protect electrical appliances from voltage spikes. These spikes can occur due to various reasons such as lightning strikes, power outages, or heavy-duty electrical devices switching on and off. The surge protector acts as a barrier between the power source and the device, ensuring that the voltage that reaches the device does not exceed a certain safe level.

The main component of a surge protector is a metal oxide varistor (MOV). The MOV is a type of resistor that has variable resistance depending on the voltage across it. Under normal conditions, the MOV has a high resistance, allowing only the standard voltage (for example, 230V in the UK) to pass through to the device. However, when the voltage exceeds this standard level, the resistance of the MOV drops dramatically, allowing it to divert the excess voltage away from the device and towards the earth. This prevents the device from being exposed to the damaging high voltage.

Another important component of a surge protector is a thermal fuse. This is a safety device that will cut off the power to the surge protector if the MOV gets too hot. This can happen if there is a very large surge or if the MOV has been damaged by a previous surge. The thermal fuse prevents the surge protector from catching fire or exploding.

In summary, surge protectors work by continuously monitoring the voltage supplied to an electrical device and diverting any excess voltage away from the device. This protects the device from damage caused by voltage spikes.