 Welcome to AND gates. In this video, you'll learn how to determine AND gate operations. To show the AND gates operations, you'll see a truth table, switch illustration, Boolean algebra equation, and an application. The AND gate is a logic device that has two or more inputs and one output. The schematic symbol for a three input AND gate is shown above. The AND gate produces a logic one at its output only when all inputs are high. A logic low state is produced when one or more of the inputs are low. As each row is highlighted, the truth table shows the changes in the input and output states of the AND gate. Notice that the output X is only one when all of the inputs are one. The series circuit can be used to illustrate the operation of the AND gate. Three switches labeled A, B, and C are used to represent the inputs and a light bulb labeled X is used to represent the output. An open switch represents a logic zero and a closed switch represents a logic one. When the light bulb is on, it represents a logic one and when it is off, it represents a logic zero. The only time the light bulb is on is when switch A is closed and switch B is closed and switch C is closed. The AND gate operation can also be expressed by a Boolean algebra equation. The symbol for an AND operation is a center dot that is read AND. It does not mean multiplication. For the three input AND gate described previously, the equation is X equals A AND B AND C which simply means that the output of the gate is logic one when A AND B AND C inputs are all in their one states. Finally, an AND gate operation is used to drill a machine part. Notice that the AND gate circuit on this drill press provides a safety feature which prevents the operator from placing a hand between the drill bit and stock. To operate, the stock is detected by a sensor and both buttons must be pushed simultaneously to activate the drill. Thank you for watching AND gates. If this was helpful, why not subscribe and give us a like.