But what if you accidentally (or purposefully) use the wrong adapter? In some cases, the plug won’t fit. But there are many instances where an incompatible power adapter will plug into your device. Here’s what you can expect in each scenario: Also, under the “current too high” section above, it explains that it’s OK if your power supply is rated for MORE current (amps) than the device needs; the device will only draw the current it actually needs. But it’s not good to use a supply rated for less current.

Next, you want to look at your device for the DC input. You’ll usually see at least the voltage near the DC plug receptacle. But you also want to make sure the current matches, too. Most are either a brand we never heard of or just a generic “ac adapter” where you’d otherwise see a brand. The second key is smaller than the first, 1.5±0.1mm (0.059±0.004in) wide ending at a radius of 6.4±0.1mm (0.252±0.004in) from the connector centre. The corresponding notch in the female connector body is 1.8±0.1mm (0.071±0.004in) wide and ends at a radius of 6.2±0.1mm (0.244±0.004in) from the connector centre. Although there is a risk of short-circuiting a battery charger, the risk is minimal and often mitigated by the circuitry of the battery charger itself. On the other hand, the short-circuit current of the lead–acid batteries installed in vehicles is sufficiently great, that a short circuit could result in a fire or explosion. The priority is therefore given to avoiding short circuits of the vehicle battery, rather than of the charger. Some adapters DO include the brand of the device/appliance they came with on the same label with the specs (great if you only have ONE device of that brand).Is there such a thing as a (relatively) high current variable voltage adapter which is capable of furnishing (relatively) high current levels, with voltages that can be incrementally increased from very low to levels that seem to make a device operate properly? Of course, it would be a test instrument and not an adapter per se. But such a device might help a user determine what the actual input voltage a device needs without trying random power adapters and taking a chance on frying the device which it is intended to power up. Each AC/DC power adapter is specifically designed to accept a certain AC input (usually the standard output from a 120 V AC outlet in your home) and convert it to a particular DC output. Likewise, each electronic device is specifically designed to accept a certain DC input. The key is to match the DC output of the adapter to the DC input of your device. Determining the outputs and inputs of your adapters and devices is the hard part.

Your article starts out describing my dilemma almost to a ‘T,’ then never does really answer the question, how do I know which adapter will work with which device. But next week I have a device coming that also has a US 2 pin plug but is rated much lower than a set of hair straighteners, rated at 5v/2a.

In the past I experienced the same as you with 99% of universal or “multi-voltage” power adapters to be cheaply made with little to no documentation or practical information about how to use them with whatever electronic device you are trying to power until I found the ProTechTrader ones. They have instructions that are in a way similar to the post explaining the basic usage and how to properly match the voltage and amperage to the current needed by the device. They also had a nearly identical disclaimer as you mentioned as well as reversible polarity tips which I haven’t seen available on most of the others floating around. I have to see if I can find a link to the manual online somewhere to show you what I mean, but this post is excellent and goes into even more detail anyway. I got a few of the 30w ones here: You go to the store for a replacement supply, and they have two kinds of 20 volt power supplies, a 65 Watt and a 90 Watt. (Which is actually the case at my local computer shop, NCIX, except they’re 19 volts. But 20 makes for simpler math.) Which one should you choose? Many mobile phones use DC connectors that are unique to the manufacturer, or even a specific phone. In the interest of improved interoperability of phone battery chargers, major manufacturers have agreed to standardize on the micro-USB connector for new phone chargers from 2010. [16]