Logic Gates
Logic Gates is a set of tiny switches inside circuits that make yes-or-no choices based on their inputs.
Think of it this way
A light switch controls one bulb: flip it up, the light turns on; flip it down, it turns off. A logic gate works the same way, but uses tiny electric signals instead of a physical switch. Two signals enter a gate, either on or off, and the gate puts out one signal based on a simple rule. An AND gate only puts out "on" if both input signals are on.
Explaining logic gates by grade level
A circuit has small switches inside it. Each switch checks a signal and says yes or no. When you link switches, they can solve problems. A number converter uses these switches to change one code to another.