What is the V switcher on a PSU for?

[FeignFeign]

on my PSU there is a red switch that switches from 115 and 230 V. What does this exactly do? if i switch from 115 V to 230 V does the psu in draw in more electricity or something? will my computer blow up or something if i switch to 230V when i wasnt supposed to ?

this is my PSU if you are curious

Newegg.com - COOLER MASTER eXtreme Power Plus RS-500-PCAR-A3 500W ATX12V V2.3 Active PFC Power Supply - Power Supplies

 

[just a noob]

if the power coming from your wall is 230 volts, then it needs to be set to 230 volts, if you try that on a 115 volt wall outlet, you would most likely fry whatever is hooked up to the psu, and it would trip the circuit breaker in the house/blow up a fuse