A surge protector is exactly what the name suggests, it protects your electronic devices, appliances and equipment against voltage surges which occur when there is an unintended change in the electrical charge in your circuit going to the power outlet.
Voltage is simply the difference between positive and negative charges that allows your current to flow. Too much voltage can result in too much charges which can fry and damage your electronic devices.
The surge protector helps prevent voltage surges by shunting the extra current through a semiconducting material to a grounding wire which connects to the third prong on your plug. This will send the excess electricity back to the return line in your building’s wiring which may result in a trip in the circuit breaker but will not damage the electronic device plugged into the surge protector.