# For one colored led matrix, common anode== common cathode?

For a single colored led matrix, are common anode led matrices the same thing as common cathode led matrices?

In this picture, the author made a distinction between the two but one can simply rotate the pictures to make them match each other. Hence, does that mean they are the same?

Likewise, for a bi-color led matrix, common anode and cathode will be different?

Let me know what you guys think? I am writing a blog about this soon and can use some clarification.

Cheers,
Jason LEE

To describe a matrix as 'common anode' or 'common cathode' is silly in the first place.
If all of the elements had their anodes or cathodes ganged together, and your examples do not, then they would have something in common.
And that would be a different story.

The OP's examples

xerxesbear:
For a single colored led matrix, are common anode led matrices the same thing as common cathode led matrices?

Unfortunately, on eBay and elsewhere, the terms "common anode" and "common cathode" are used when describing 8x8 LED matrices.

The proper nomenclature should be "row anode column cathode" or "row cathode column anode".

But as the OP says, rotate the matrix by 90 degrees and the rows are now the columns, so...

Well, the convention is this: on the back of the matrix there are two lines of pins. These are taken to indicate which direction the rows of LEDs are arranged in. The columns are perpendicular to the pins.

For bi-colour and tri-colour matrices, the terms "common anode" and "common cathode" make a little more sense. Although there will be both common anodes and common cathodes, there will be twice or three times as many of one versus the other, and if you think about an individual led within the matrix, it will be either common anode or common cathode.