Blog 9: Travel Voltage Converter

Once again reliving my memories of my trip to Vietnam, I now see the physics behind one of the most overlooked yet important pieces of travel equipment: the voltage converter. 

The many faces of an unsung hero

Because different nations have different power systems, the voltage that is contained in power outlets is not always the same. The voltage in Vietnamese power outlets is 220 V, whereas American power outlets run at 120 V. 

The voltage difference presents a major problem. If you plug in your American device, which is constructed to run on 120 V, into a 220 V outlet, there is a difference of 100 extra volts that flow into your device. That voltage difference, as we were warned by Mr. Brown (a trusty veteran of Vietnam travel), could cause the entire hotel to black out, and fry your device.

Now, what is more important here?

Wait - 100 V isn't very much, considering that a Van de Graaff generator can produce about 400,000 V. So how can 100 V cause such a stir?

Well, voltage is a ratio of energy to charge. The Van de Graaff may produce 400,000 V, but the ratio may be 40 joules / (1/10000) Coulomb. However, 100 V in a power outlet could mean 100,000 joules / 1000 Coulombs, which means that there is a large amount of electrons, and thus a large amount of energy. That is why 100 volts running through your device could mean doom for its circuitry. 

During our first night's stay, some idiot forgot to use a converter, so Tan My Dinh Hotel had a black-out. Though someone got stuck in the elevator, the worst part about the black-out was the absence of TV or air conditioning for an hour. Lesson learned - don't go traveling without a voltage converter!