https://blog.gongquiz.com/2021/07/22/%eb%b0%9c%ec%a0%84%ea%b8%b0%eb%a5%bc-%ec%a0%95%ea%b2%a9%ec%a0%84%ec%95%95-220v%eb%a1%9c-%ec%a0%84%eb%b6%80%ed%95%98-%ec%9a%b4%ec%a0%84%ed%95%98%eb%8b%a4%ea%b0%80-%eb%ac%b4%eb%b6%80%ed%95%98%eb%a1%9c/