Chapter 6 Question 002

Why does a laptop work on any country's electricity standard, but most other appliances don't? (Minsu Bey) At present, the domestic electricity provided by the American power system is 110 volts, and in many countries it is 220 volts.The laptop's power cord has a built-in transformer that allows the computer to operate properly on both standards.Conversely, televisions and refrigerators can only operate on one standard.If you want to use an American refrigerator in France, you must buy a separate transformer to convert the French 220 volts to 110 volts.Similarly, to use Korean TVs in the United States, you can only buy a separate transformer to convert the 110-volt power supply in the United States to 220-volt power.

Why can't these appliances be used everywhere like laptops?It is slightly cheaper to send 220 volts than 110 volts, and it is also slightly more dangerous.Which transmission system to use has been fairly extensively debated in most countries, and once a decision has been made, the country has invested heavily in the chosen system.Therefore, it is unrealistic to expect countries to switch to unified power supply standards in the near future.Therefore, people who travel internationally with electrical appliances need to find ways to ensure that these appliances can be used under different power supply standards.

Putting transformers inside all electrical appliances would undoubtedly satisfy this need, but doing so would increase the manufacturing cost of the appliances.The vast majority of refrigerators, washing machines, televisions, and other electrical appliances probably won't have the opportunity to travel abroad, so the extra cost of adding built-in transformers to them is not justified. Laptops are an exception, especially in their infancy.At that time, most of the people who bought laptops were business people who needed to take them on business trips at home and abroad.For these people, carrying a heavy transformer on an international flight is an unacceptable burden.So, laptop makers built transformers into their computers from the start.