Connect with us

Power adapter question (newbie)

Discussion in 'General Electronics Discussion' started by J100, Jun 16, 2014.

Scroll to continue with content
  1. J100


    Jun 16, 2014
    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 -

    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
  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    Nov 28, 2011
    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.
  3. J100


    Jun 16, 2014
    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.
    KrisBlueNZ likes this.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day