Power Adapter Check

Two different things get called an “adapter” and confusing them is how people melt hair dryers.

A plug adapter is a passive shell. It lets your plug fit a foreign socket and changes nothing electrically. It costs a few dollars and weighs nothing.

A voltage converter (or transformer) actually changes 230V down to 120V, or the reverse. It is heavy, it is expensive, and almost nobody needs one any more.

The label is what decides it, not the country

Turn your charger over and read the small print near the plug. You are looking for the input rating:

• INPUT: 100-240V, 50/60Hz means the device handles every mains supply on earth. You need the plug adapter only. Every phone charger, laptop brick, camera charger, and electric shaver sold in the last fifteen years says this.
• INPUT: 120V or INPUT: 230V alone means single voltage. Plug it into the wrong country and it either burns out or does nothing.

That one line settles the question for the specific device in your hand, which is why it beats any general rule.

What still needs a converter

Anything that makes heat or spins a motor, because those cannot be made dual-voltage cheaply:

• Hair dryers, travel irons, curling tongs, kettles
• Older electric shavers and some clippers
• Cheap desk fans and small kitchen appliances
• Anything with a mechanical clock motor

For hair dryers specifically, do not buy a converter. Buy a dual-voltage travel dryer instead. A converter big enough to run a 1,800W dryer is the size of a brick and costs more than the dryer.

Frequency, the part everyone forgets

The Americas and Japan run at 60 Hz. Most of the rest of the world runs at 50 Hz. Electronics do not care. Anything with a synchronous motor does: a 60 Hz mains clock will lose about ten minutes an hour on 50 Hz, and some motors run hot. Japan is the odd one out and splits internally, 50 Hz in the east including Tokyo, 60 Hz in the west including Osaka.

Grounding, the part that actually matters for safety

Cheap universal adapters often drop the earth pin. For a two-pin phone charger that is fine, it was never earthed. For anything with a metal body and a three-pin plug, it is not. Buy an adapter that carries the earth through, and if you are going to the UK, note that Type G sockets are shuttered and will not open at all unless the earth pin goes in first. Some adapters cannot open them.

A note on the count

One universal adapter plus a small power strip from home beats four adapters. Adapt once at the wall, then plug your own strip into it and everything else into that.