Power adapter question (newbie)

[J100]

Hi, I have a newbie question, hopefully someone is willing to help me out.

I need to replace the power adapter for an Alesis Q49 keyboard. It requires 9V DC 500mA, Pin Positive, 5.5mm outer diameter.

Is the one below correct? I'm not sure because it says "charger", and I've heard adapters for chargers can actually be a higher voltage than listed. Also it's listed as "AC", but then in the description it says "DC". I don't know how to make sense of that.

Thanks -

http://www.ebay.com/itm/9V-200mA-AC...=Laptop_Adapters_Chargers&hash=item3f288bbd59

9V 200mA AC Adapter 300mA Power Supply Cord 5.5mm 2.5mm Tip 2.1mm 500mA Charger

Compatible Replacement New DC Adapter Charger Power Supply PSU

Features & Specifications:
100% Generic New and High Quality Compatible Replacement
Input Voltage : AC 100-240V (Worldwide AC Input)
Input Frequency : 50-60Hz

Output Voltage :9V 1A Max Center +
Connecter Size : 5.5mmx 2.5mm/2.1mm

Note: Please make sure the DC output and tip size of ac adapter are accordant before you bid.
Industry Quality : Over Voltage Protection, Over Heat Protection, CE

Package include:
1 x AC/DC Adapter Home Wall Charger Power

 

[KrisBlueNZ]

Hello and welcome to Electronics Point

That adapter looks suitable for your requirements. At USD 3.99 it is unlikely to be very good quality; this may result in shortened lifetime (i.e. it may go pop or start a fire) and possibly problems with noise, but according to its specifications it should be suitable.

The words "adapter" and "charger" are often used interchangeably, to mean a power supply that delivers a fixed voltage with a certain specified maximum current. An electronic device can use this power source to supply power for its operation, and if it has a rechargeable battery, it can also use this power source to recharge the battery. The control and monitoring of the battery during the charge procedure is done by circuitry inside the device.

You can also buy stand-alone chargers for removable rechargeable cells (NiCd, NiMH and other types, in AAA, AA, C and D sizes) that charge removable batteries directly. These contain a power supply and circuitry to control and monitor the batteries during the charge process. These aren't appropriate if your electronic device has an internal non-removable battery.

The connector seems to match your requirements but the barrel length is not specified, and even if the numbers match it's possible that it won't fit, or won't fit properly and make reliable contact. The only way to find out for sure would be to try it.

 

[J100]

Ok KrisBlue, thanks for the detailed answer. I am just trying to understand how these power adapters work, so I can order them online without confusion.

I figure that one would probably work, but I ended up buying a different one, which was listed as compatible with my keyboard. The cost was a bit more. I don't know whether it is better quality or not but at least it is advertised as working with my device, which made me feel better about ordering it.