Introduction to Logic Gates

Student Activities

A logic gate is a simple device that returns some number of outputs. These outputs are determined by a pattern of inputs and rules the gate follows to create a desired result. At their core, gates return either as "true/on" or "false/off". Logic gates are the foundation of not only computational thinking and coding but also apply to electrical engineering and algebraic thinking. In this activity, students create a series of simple logic gates, and then are given an opportunity to apply these gates to create simple contraptions.

NOT Gate

• A NOT gate is a great introductory gate to create. In this gate, students create a signal that is inverted from its input. If you trigger the input with a lever, turning the lever on will in turn respond with a FALSE signal that the gate is turned OFF.

AND Gate

• An AND gate uses two inputs, not just one. In order for an AND gate to return "True" or "On" both inputs need to be connected. If you use two levers, for example, both of them need to be on in order to activate the machine or contraption.

NAND Gate

• A NAND gate is basically the NOT gate equivalent of the AND gate. Instead of sending an active signal when both its inputs are active, the NAND gate will deactivate the signal its sending out. Turning on just 1 level will not deactivate the mechanism connected to the NAND gate’s output.

OR Gate

• An OR gate is almost the opposite of an AND gate. If any of the inputs are turned on, the mechanism connected to them will also turn on. Only when all of the inputs have been turned off will the mechanism turn off. Think about OR as If A, B, OR C is true, the machine turns on. For an AND gate, A, B, AND C would all need to be true for a contraption to turn on.