The US and Japan use 110V as a standard value. The rest of the world uses 220V excluding some exceptions. This difference creates a problem in using electronic devices in different countries. As a result, when we travel from the US to any other country, we don’t find 110V power supplies to charge up or operate our electronic appliances. If you connect the 110V compatible devices to a 220V outlet, the gadget will burn out!
However, there’s a solution to this problem. You can use voltage converters or voltage transformers to turn the 220V supply into 110V. Though converters and transformers will do the same job, it’s better to use a transformer.
Using a transformer in a country which uses 220V
Transformers can increase and decrease voltages depending on the number of turns on each of their windings. If the primary coil has more loops than the secondary coil, it’ll be a step-down transformer, and will decrease voltage; and vice versa.
So, in our case, we need a step-down transformer. However, we need to check out the turn ratio. It has to be 2:1 for the primary to secondary winding because only then it’ll decrease the voltage to a value of half the previous voltage. Transformer’s voltage and turn ratio’s relationship is:
So, when Np (number of turns in the primary coil) is twice the value of Ns, we get half the voltage. As we’re using 110V gadgets with 220V supplies, we need to cut the voltage in half and the step-down transformer with a 2:1 turn ratio meets the necessity.
Using a converter in a country which uses 220V
Converters convert the voltage. What they do differently from the transformers is that they chop the voltage’s sine wave in half. It means if you use a converter, you’ll get the output voltage half of the initial value of the voltage supply.
Based on the turn ratio, a transformer can multiply the voltage many times or cut it in half, or one-third, or any fractions, but the function of a converter is specific. It’ll only divide the voltage in half.
As we’re in need of turning 220V to 110V, we can use a converter. If our needed voltage wasn’t the mathematical half of the primary voltage, we couldn’t use a converter.
Which one is the best way: transformers or converters?
Converters are less suitable than transformers. Converters aren’t preferable for electronic appliances that need a high wattage. Converters are generally of low wattages. You cannot use all your gadgets with converters as some devices might have high wattage.
If you don’t know the wattage of your devices, check the voltage and current measurements on its plug, and multiply them. The result you get is the wattage. You have to use transformers or converters that can support the wattage of your gadgets.
If you want to play it safe, you should buy a step-down transformer. Using a transformer will be the best way to use an electronic gadget from the US (single phase voltage 110v) to a country which uses 220v.
Most electronic gadgets have inbuilt universal motors. Because of this, they can run on both DC and AC. The phase difference and the frequency also don’t make any change. We have to convert the voltage only.
So, buy a transformer for your travel kit because you’ll need it the most when you’re traveling outside the US.
- Quora, How do I use a 110v appliance in a 220v outlet? I bought a cheap step down converter online. I already have an adapter. What do I need to use to make sure this appliance doesn’t fry? Can I leave it be since it’s 110v in 220v?
- David Porter, The Ultimate Electricity Guide for World Travelers, March 21, 2012
- Jeffrey Bausch, Why doesn’t the US use 220V like everyone else in the world? – 09/30/2016