Monthly Archives: January 2014

January 29, 2014 by

What on earth is polarity?

Wikipedia says:

Electrical polarity (positive and negative) is present in every electrical circuit. Electrons flow from the negative pole to the positive pole. In a direct current (DC) circuit, one pole is always negative, the other pole is always positive and the electrons flow in one direction only

I say: No need to worry too much about what it means, you just need to make sure you’ve got it right. You risk damaging your device if you use the wrong polarity power adaptor.

If you’re buying a replacement power adaptor from MyVolts, you can rest assured: power is our business, and we know the correct polarity for all the devices we sell replacement power adaptors for, so when you buy from us you don’t need to worry – we get it right.

But if you’re matching a power adaptor from your rat king, or you just want to know more:

There’s a little diagram on every AC/DC power adaptor label that illustrates what the polarity is – that is, if the power adaptor is centre positive polarity or centre negative polarity.
The diagram shows a semicircle with a dot in the middle – and there is a plus sign and a minus sign pointing to both semicircle and dot. Which sign is pointing to the dot in the middle is what denotes its polarity – like below:



Here’s what it looks like on a power adaptor – see the little diagram in the bottom left hand corner on the label:

9V polarity centre negative

9V polarity centre negative

And lastly a close up: – you can clearly see it is centre negative:


You can always contact us if you’re not sure – tell us the make and model of your device and we’ll advise just the power adaptor you need.