ABOUT CURRENT
When electricity was first discovered,
nobody knew what it was, it was just this mysterious stuff that flowed
in wires. They arbitrarily called one end of the battery positive and
the other negative, and said that current flows from positive to
negative.
Later
they found that the wires are full of tiny things called electrons, and
they're what's moving when an electric current flows.
Unfortunately, it turned out that the electrons have a negative
electric charge and flow from negative to positive. But they didn't
want to have to redraw all the arrows in their textbooks[1], so they
kept on saying that current flows from positive to negative. This is
called "conventional current"[2] and it's the way we drew the arrows on
the circuit a couple of pages ago.
That's how current flow works
in metal, anyhow. When we come to look at silicon, we'll find that
things are sometimes a bit different.
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[1]
Don't look so bewildered. Remember, there was no Microsoft Office in
those days. Books were written on actual, physical paper and changing
them all would have been a really big job.
[2]
After the so-called Great Embarrassing Convention of 1898 where the
scientists all got together, looked very sheepish, and decided what to
do about the problem.