Archive for July 2010

How to read Universal AC Adapter schematics

July 20, 2010

I’m currently involved in a project to power small electronic devices without batteries. I’m using a universal AC Adapter that I bought cheap and modified the adapta plug on.

I was modding the adapta plug to power a small cassette player and now mp3 player for the home. Before I did this, I needed to know about the connection rules so I wouldn’t fry my equipment.

I went out and bought the adapter and forgot how to read polarity schematics. So I went online to review, and figured I could write it down here for future references. So when I become super lazy, I only have to log into my own WordPress page to find it.

Find the diagram that shows three circles connected by lines. The center circle will be open on one side. Whichever sign it opens to is the polarity of the tip. If the circle opens to the plus sign, it is tip positive. If it opens to the minus, sign it is tip negative.

example of "tip positive" polarity schematic

So there you have it. Or I have it…either way it’s there.