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A logic gate
A logic gate is a tiny decision made with electricity. An AND gate turns its output on only if both its inputs are on. An OR gate turns its output on if either input is on.
You use them every day. A doorbell with buttons at the front and back door works like OR: either button rings it. A machine that needs both hands on two buttons before it starts, so a hand cannot be in the way, works like AND.
A light should come on if either of two switches is on. Which gate is that?
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