AC voltage differences.
Physics101. Alternating current (AC) is what is in the wall while direct current (DC) is like what is in your car's cigarette lighter socket. Today, let's go over some important things to consider about AC power when traveling to South Korea. We must consider two things 1) Voltage and 2) Plug shape.
You'll find that plugs that come with two flat pins usually are built for 110-120V and plugs with two round pins are built for 220-240V. Let's address the most pressing difference first: current (measured in volts). Korea most generally runs a current of 220-240 volts so that must be taken care of first. But before you go out and buy a new travel razor or cell phone charger, check the backside of your device.
If you take a look at the power brick of most electronics, many mid-to-high end electronics already have the voltage capabilities to function perfectly fine in Korea, as well as other countries. For example, my laptop power brick lists the device at capable to run from 100-240V. Score! But alas, my beard trimmer is rated at 120V only - so it must stay stateside.
Once you have identified what will not explode once plugged in, now you must find something to change the plug/prong shape. Below is a cheapie but a goodie that attaches to the end of your appliance. The one pictured below is for U.S.A -> R.O.K. Also, don't panic - my adapter cost me about 50 cents (500 원) in Korea.
Another common solution specifically for laptops is purchasing a new cord that connects from the power brick to the wall. Consider that the three-prong female-end laptop cord is somewhat universal in design. Where the difference lies is the regional plug shape. Meaning, if you went to a Korean electronics store, you can pick up a professional quality laptop cord to go from your power brick to the wall. I think they run less than 만 원 (around 10 bucks).
Below is a list of common plug types. If you see a red X, you need a plug adapter.
I must reiterate that changing the plug shape is not enough - if you plug something in that is rated for 110-120V into a Korean wall socket with a plug adapter - you will see sparks, smoke, and/or Jesus. Play it safe and check the voltage. Essentially, if you can't get a hold of an adapter and/or your product isn't rated for 220-240V (like my trimmer) then that's where transformers come into play. Hook up with a friend who has one of these little dandies and you are in luck.
Transformers (트랜스퍼머) step down the current to a native-like level for several hours. It isn't recommend to use such transformers for extended periods such as days, weeks at a time because the electricity being stepped down isn't always "clean". Remember those other numbers on the laptop power brick? Sometimes the "stepped down" current can also spike those other numbers after prolonged use. Worried about charging your DS? Don't be. Transformers are safe, just remember that they are not a good idea for devices like TVs, laptops, or other long-term use appliances.
Some big name hotels and boarding houses geared for foreigners (like university dorm rooms) will likely have a few transformers to check out.
I wonder if anyone has any "shocking" stories to tell (sorry - I couldn't help that one).
Thoughts?