Line conditioners and surge protectors both help to prevent voltage in your devices from shooting up and damaging computers, game consoles, or other machines which use a power cable rather than batteries. In everyday use line conditioners can prevent changes from voltage in making the lights or dim or brighten, meaning you can have a consistent supply of 120 volts per second.
Surge protectors on the other hand are smaller and cheaper than line conditioners, these prevent high-voltage from being transmitted to your device, so excessive power doesn't cause your machine to die, or suffer catastrophe. Surge protectors needs to be replaced every few years so in the long run this can make them more expensive than line conditioners.
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