As long as the correct voltage is used, a device will draw only the amperage it needs, meaning there will not be “too many amps”. If an incorrect voltage is used — say a higher voltage than the device is rated to accept — then yes, too many amps may be drawn, and the device can be damaged. This is why it’s critical to use the correct voltage. Can I use an AC adapter with higher amps? If you look closely at the small print on many power supplies, you’ll see they’re rated for anything from 100 to 250 volts. This means most can work worldwide with nothing more than an adapter to account for the physical plug differences — no voltage transformer needed. When replacing a charger, this is easy to determine: it’ll be listed somewhere on the old charger. In your case, the old charger supplied 19 volts, so your replacement must also be 19 volts. And here’s the problem: there’s no way to say what’s enough or too much. It varies from device to device. Some may tolerate a wide range of input voltages, while others are extremely sensitive to even the smallest error.

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As long as the voltage matches that expected by the connected device, then yes, you can use an AC adapter capable of providing higher amps. Can I use a 5V 2A charger with a 5V 1A device? Particularly when it comes to popular circular power connectors, make sure the expectations match. If the device expects the center connector to be positive and the outer ring to be negative, your power supply’s connector must match. There’s no getting around this. No, amps do not have to match, but the power supply or charger must be able to supply enough amps as required by the device being powered or charged. In practical terms, that means the amperage rating of a power supply or charger must match or exceed that required by the device it is connected to. Does more volts mean more amps? The device being uses wants to let xx amps through it and wants to take it from the charger. If the charger cannot supply enough of the current that the device wants, if may decide that it doesn’t have enough to run. That is where the pull analogy comes from.

Voltage

Most power supplies provide their output on two wires: one labeled (+) or positive, and the other (-) or negative. Which wire is which is referred to as polarity. Very good explanation. Two other problems arise, though. The TYPE of voltage. While most chargers are DC, some are AC or pulsating DC, which just will NOT work place of the correct one. AC chargers are usually represented by a tilde (~), and pulsating DC chargers are indicated by a solid line over a dotted line, kind of like highway dividers where there’s no passing in one direction. Dell Laptops have that center pin, I forget what the interface is called, but it makes it likely that other chargers won’t work. I bought a higher amp Dell charger to replace my busted one, and it works great, but I had a Dell parts expert guide me to the right choice

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Thus, as long as you replace your power supply with one capable of providing as much or more amps than the previous, you’ll be fine. In other words, there is nothing wrong with having a charger capable of providing more amps than needed. Polarity Yes. Because a) the voltage matches, and b) the amperage provided is greater than that needed, you can use a 5v-2A charger with a 5V-1A device. Is 500ma the same as 0.5 A? Sidestep all those unknowns and make sure to get exactly the right voltage from the start. Amperage The problem, of course, is the reverse: if your device needs 1.0 amps, but your charger is rated at only 0.5 amps, then any of several problems could result: It’s very important to get the right voltage. Some devices are tolerant of variations and work just fine. Others, unfortunately, are not tolerant at all. Depending on how different the supplied voltage is from what’s required, the device may simply fail, it may work “kind of”, or it may appear to work at the cost of a much shorter lifespan.Leo, I agree with your analogy re power supplies. However, your statement that voltage is constant is not correct. If you load up a power supply, you will have losses in the wire that connects the supply (wall wart) to the device. Engineers like to refer to this as I The input line voltage (wall or “mains” power) must be supported but is unrelated to compatibility with the device being charged or powered.

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The amperage rating of a charger or power supply is the maximum it can supply. A device being charged will only take as much amperage as it requires. If your device needs 0.5 amps to charge, and your charger is rated at 1.0 amps, only 0.5 amps will be used. Oh Leo, you’re a great IT guy but not so hot at getting electronics across to beginners. I could agree with your definition of Voltage – the ‘push’ on the electrons that tries to make them move and make a current, but not your definition of Current. The load / laptop / whatever does NOT pull – it lets the current through; faster if the resistance is low, slower if it’s high. Current is how fast the electrons (that carry the charge) are moving. I am an electronics guy and am with Leo on this one. Andrew’s comments are more about the internals of a device being run but the question was about the current rating of a charger. Just be careful with some laptops. I know that with my Dell laptops, if the chip in the charger goes bad (the chip that tells the Dell laptop that this charger is the correct charger for the computer), it will no longer charge the battery, and the laptop will draw less power (or amps – but Amps times Volts gives you Watts – or power) – thus slower laptop. Their reasoning, is so you don’t plug a charger in that isn’t rated for your laptop and damage it, but it forces you to only buy the correct Dell chargers, and when that chip goes, even if the charger is working – you no longer can charge, and you have a slower system (even my USB ports wouldn’t produce the correct power output when the Dell isn’t able to read the charger’s chip.)Here’s the catch: just because the physical plug fits into your device does not mean that the polarity is correct. Example of a polarity indicator. (Image: Three-quarter-ten, CC BY-SA 3.0, via Wikimedia Commons) The other problem is size of the coaxial connector, and the combinations are nearly endless. There is the I.D. or Inside Diameter, which is what size the pin will fit into, and then there is the O.D. or Outside Diameter, which is the outside ring that plugs into the device to be charged. The amperage provided by your charger must match or exceed what the device being charged requires. Amperage Provided Versus Amperage Required Power Supply or Charger Amperage Rating If it’s not made specifically for your particular computer, getting the right power supply is important and involves matching voltage, amperage, and polarity.