The 8 Best Voltage Converters
This wiki has been updated 20 times since it was first published in April of 2015. If you're addicted to your phone, tablet, or laptop, don't get on a plane without one of these handy and feature-rich voltage converters, to make sure you can power up your devices wherever you're headed. We've included models that are compact enough to slip in your hand luggage, and larger, more powerful ones that you may need for higher-draw appliances, like hair dryers. When users buy our independently chosen editorial recommendations, we may earn commissions to help fund the Wiki. Skip to the best voltage converter on Amazon.
If you send the current through in the opposite direction, you will effectively half the voltage.
Now, my driving instructor taught me never to wrap my thumbs around the steering wheel, so if I got in a wreck I wouldn't shatter the bones in my thumb joints.
A voltage converter employs some incredibly complicated electromagnetic principals. Without getting into the particulars of ideal and real electrical transformation, we can understand the process of taking a 110 V outlet and getting 220 V out of it (and vice versa) by simply grabbing hold of a steering wheel.
When you use a voltage converter for electrical transformation, you send an alternating current through one wire that's wrapped around a one side of a soft iron core which is shaped like a square doughnut. There's another wire wrapped around the other side of the core, directly across from the first.
To make sense of this, take your hands and put them on an imaginary steering wheel in front of yourself. Imagine the wheel is actually square if you want to get closer to the reality of the transformer, and put your hands in the 3 o'clock and 9 o'clock positions. Now, my driving instructor taught me never to wrap my thumbs around the steering wheel, so if I got in a wreck I wouldn't shatter the bones in my thumb joints. It was good advice, so we're only going to consider the other four fingers on each hand (this also makes the math a lot easier).
At this point, you've got four fingers wrapped around each side of the steering wheel. Think of each hand as its own wire, and of your fingers as what physicists call turns, or the times that a wire wraps around a core. Imagine you pass a current into your right hand at 110 V. That current will pass over to the left hand through a process called electromagnetic induction, which the iron core amplifies and stabilizes. With four turns on each side, you get 110 V in the right hand and 110 V in the left.
Now, take two fingers away on the right hand. Suddenly, you have twice as many turns on the left side of the core as on the right. If you pass the same 110 V through the right hand with its two fingers, the doubled turns on the left side will give you twice as much voltage. 110 V becomes 220 V, and you've effectively transformed your electrical outlet. If you send the current through in the opposite direction, you will effectively half the voltage.
This is the case in an ideal transformer Transformers in practice lose voltage for a variety of reasons. With that in mind, the manufacturers of these converters take many mathematical pains to land your transformation in a safe and useful voltage range.
I, for one, cannot live without my blender. I spent a ridiculous amount of money on it, and I eat at least one meal out of it each day. Staying abroad for any length of time is expensive enough; knocking back a few homemade smoothies each day saves you countless dollars, or euros, or pounds–whatever the currency. And I do, in fact, travel with this blender.
I spent a ridiculous amount of money on it, and I eat at least one meal out of it each day.
The problem is that the blender runs about 1,400 watts at 11.5 amps, and it's exclusively a 120 V unit. You may or may not be aware, you can derive the wattage of your appliances by multiplying their operating voltage range by their current, measured in amps. So, 11.5 amps x 120 V = 1,380 watts, which I rounded up to 1,400. If I subjected that motor to a 240 V outlet in Europe, I'd be introducing it to twice the wattage, at 2,760 watts. Not exactly great for the blender.
To safely convert an appliance of this magnitude (your irons, hair driers, and straightening/curling irons also eat up a lot of watts), you want to get a transformer than can handle two to three times the wattage of your most power-hungry appliance.
As you peruse the available converters on our list, ask yourself what the highest wattage is for which you need conversion. Then find a converter that at least doubles that capability. If you don't see the wattage listed on your appliance, look for a measure of the unit's amps and apply the formula above.
Transformed From The Outset
Voltage conversion was born right alongside our control of electrical power itself. Most economically transmitted sources of electricity are too powerful to practically meet any household application, so even the earliest alternating currents had to undergo transformation before anyone could make use of them.
Use a higher voltage at a higher current and that wire will get exceptionally hot as energy diffuses through it.
When electricity travels along a wire, higher voltages traveling at lower currents will lose less power as they move through said wire. Use a higher voltage at a higher current and that wire will get exceptionally hot as energy diffuses through it. This is particularly useful in toasters and hair driers, but it wouldn't work so well for a bird alighting on a power line, nor would it be particularly efficient.
Thomas Edison, who's often given a blanket credit for anything and everything to do with electricity, actually made most of his discoveries and drove the majority of his inventions forward using direct current, which proved far inferior than the combination of alternating current and transformation.
So, from the earliest attempts at transmitting alternating currents in the late 1800s, Edison's competitors used higher voltages along with transformers to regulate the voltage of electricity entering an appliance, a method which quickly became the standard.
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