Forget everything you think a computer does.
At its core, a computer only does one thing.
It decides.
Yes or no.
Let electricity through, or don't.

Everything on your screen, every photo, message, video,
comes down to that one decision, made billions of times a second.
That's it. That's the whole thing.

But what actually makes those decisions? How does a computer know when to let electricity through, and when not to?