2.4 boolean logic

• What is the CPU made up of?

  Millions of tiny switches called transistors
• Why do we use binary to represent transistors?

  Because transistors can be either on or off
• What does a binary digit represent?

  Either 0 or 1
• What does 0 represent in binary for transistors?

  A transistor that is off
• What does 1 represent in binary for transistors?

  A transistor that is on
• What is the purpose of truth tables?

  • Show output of logic gates
  • Show output of logic circuits
• How do you calculate the number of rows needed for a truth table?

  Use $2^{\text{number of inputs}}$
• How many rows are needed for a truth table with 4 inputs?

  16 rows
• What is the first step to create a truth table?

  Calculate how many rows are needed
• What should you do after calculating the rows for a truth table?

  List the values for each input
• What is a Logic Circuit?

  Two or more logic gates used together
• Why is the order of gates important in a Logic Circuit?

  It affects the output of the circuit
• How can logic circuits be represented?

  • Using diagrams
  • Using truth tables
• What does the NOT gate do?

  Inverts the input
• What is the output of an AND gate?

  1 if both A and B are 1
• What is the output of an AND gate if either A or B is 0?

  0
• How is the AND gate written symbolically?

  AΛB
• What is the output of an OR gate?

  1 if either A or B are 1
• What is the output of an OR gate if both A and B are 0?

  0
• How is the OR gate written symbolically?

  A∨B
• What is a logic gate?

  Components that provide a single output
• What is a logic diagram?

  A diagram showing logic gates
• What are transistors?

  Components in the CPU that can be on or off
• What is a truth table?

  A table representing outputs of logic gates
• What is a logic circuit?

  Two or more logic gates used together
• What is binary?

  A number system with two symbols
• What is another name for the binary number system?

  Base 2