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How to Choose the Best AC Adapter for Your Device

AC adapters are useful accessories for ensuring a dependable power supply for a multitude of electronic devices. With so many options available, it is important that you have the knowledge to choose the right fit for any device.

What Is an AC Adapter?

An AC adapter is an external power supply which converts an alternating current (AC) from a wall outlet to a direct current (DC) needed by an electronic device. As such, it may also be called an AC-DC converter, or a charger, if used to supply power to a battery-powered device. AC adapters have several important benefits to be considered. Firstly, by having the power supply come from an external source, the electronic device it supplies can be made much smaller and lighter than if the power supply were integrated. Having a separate power adapter also reduces the amount of heat produced in a device minimizing the risk of overheating. Moreover, electrical noise is reduced when the power supply comes externally, making a device safer and less likely to be damaged by voltage spikes. Lastly, in the case of damage from brownouts or electrical fires, external AC adapters eliminate the need to replace the whole device. Instead, the damaged AC adapter can be disposed of and replaced at a much cheaper cost without losing valuable data in the process.

Check Electrical Ratings to Choose the Right AC Adapter for Your Device

Before looking for an AC adapter that matches your device, you may check to see if an adapter by the original equipment manufacturer (OEM) is available. Manufacturers will sometimes offer replacement chargers/adapters for their products. In most cases, you can find the specific adapter for a device by searching for it using the model number printed on the adapter that was shipped with it. If the OEM adapter is no longer available from the manufacturer, finding the right power adapter for your device will require selecting a compatible third-party accessory. The first step is to determine the electrical rating of the device, including its designated voltage and current carrying capacity. Polarity may also be important in some cases. Manufacturers will print such information on the labels of these power accessories, but you may also check the device’s user manual for the electrical range of its AC adapter.

Voltage is written as volts (V), whereas current rating is communicated in amps or ampere (A). It is important to look at both the AC input and DC output values for a device. Depending on the region, AC input can be either 110/120V or 220/240V but to make it easier, manufacturers usually offer adapters that support both voltages. Dual voltage adapters have AC voltage ranges listed as 110-220 VAC or 100-240 VAC. When looking for the DC voltage (VDC) look under the DC symbol on an adapter label. This value is just as important for choosing a matching device. On labels and in manuals, the AC symbol is represented as a wave, while the DC symbol is a solid dash with three short dashes underneath it.

Select an AC Adapter and Device With Matching Specifications

The AC adapter you use should have matching electrical ratings to the device it will be supplying power to. As such, the input voltage and current rating of the device must match the output voltage and current rating of the adapter. If the adapter’s current rating is higher or lower than that of the device, either instrument may malfunction. For example, even when the current values are the same, if an adapter’s voltage (VDC) is lower than the device’s input, it is likely to overheat or fry the internal circuitry within the device. Using an AC Adapter with a lower current rating will also cause malfunction because the device will try to draw more current from the adapter than is available, causing the adapter to overheat. It may come as a surprise that you can use an adapter with a higher current rating to power a device as long as both instruments have the same voltage. In this case, the device will only draw as much power as it needs from the adapter without causing undue stress on its circuitry.

It is also important to check that the polarity of the power adapter’s connector matches that of the power input or charging port of the device. These instruments may either have center-positive polarity or center-negative polarity, wherein center-positive polarity refers to a connector with a tip that has a positive polarity and a connector with center-negative has the opposite. To find the polarity of a device, you can look for a + (positive) or - (negative) sign in front of the voltage rating. In some cases, manufacturers will instead use a polarity diagram like the ones shown below. If the circle with the negative symbol is connected to the open circle like in the top diagram, the polarity is center-negative. If the open circle is instead connected to the circle with the positive symbol, it is center-positive.

Note that most AC adapters will have a center-positive polarity so this usually not an issue, however it will still be necessary to check because mismatched polarity may similarly cause malfunction.


A lot of devices can benefit from having external AC adapters but certain qualities need to be met in order to find the right fit for your device. Specifications such as current and voltage should be considered alongside factors like budget and availability to find a suitable match. For a wide inventory of electronics parts from trusted manufacturers, Alpha Aerospace Parts is here to assist you with all your electronics and/or aviation parts needs. We invite you to browse our catalog of available items on our website and submit a Request For Quote form (RFQ) to receive a competitive quote for your comparisons on any of the products we offer. Upon receiving and reviewing your form, our dedicated team will send you a quote catered to your specific needs in 15 minutes or less. Get started today to see how Alpha Aerospace Parts can serve you as your premier sourcing partner!


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