electronics made easy
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I don't really understand why, in the #3 Matrix exercise, there is no connection to ground. Apparently, all other projects require one such connection. I checked also in the example given in the Fritzing software, and there is no connection to ground.
What did I miss?
Thank you in advance.
that is a very good question. The digital Pins can act as 5V+ or as GND. So it would be possible to run an LED for example with two pins and without a GND. You would simply switch one pin HIGH ( = 5V+) and the other LOW ( = GND) – your LED will light up. The same but much faster happens with the matrix.
I hope this helps understanding.