13.4.3 Understanding sequential logic circuits

• Sequential logic circuits use memory elements like flip-flops
• A group of flip-flops is called a register
• How does a D flip-flop store data?

  At the rising edge of clock signal
• Combinational logic outputs are based on current inputs
• Order the types of sequential logic circuits based on their complexity.

  1️⃣ Flip-flops

  2️⃣ Registers

  3️⃣ Counters
• Match the flip-flop type with its description:

  SR Flip-Flop ↔️ Has set and reset inputs

  JK Flip-Flop ↔️ Avoids invalid state

  D Flip-Flop ↔️ Stores input at clock edge
• What do the S and R inputs of an SR flip-flop do?

  Set or reset output
• Flip-flops use a clock signal to synchronize data sampling and output updates.


  True
• Which flip-flop is the most versatile and allows the output to be set, reset, or toggled?

  JK flip-flop
• Sequential logic circuits depend on past states
• Combinational logic circuits require a clock signal.

  False
• Flip-flops use the clock signal to synchronize data sampling and output updates.


  True
• State diagrams use arrows to represent transitions
• A state diagram shows the different states of a circuit and the transitions between them based on the clock signal
• Sequential logic circuits require a clock signal to update their states.


  True
• Counters in sequential logic circuits count clock cycles or events.


  True
• The output of a D flip-flop changes immediately with the input data.

  False
• Why is a clock signal necessary in sequential logic circuits?

  To update states
• SR, JK, and D are examples of different types of flip-flops
• What are flip-flops used in sequential logic circuits?

  Memory elements
• The JK flip-flop toggles the output based on the J and K inputs
• What happens to the output Q of a D flip-flop when the clock edge occurs?

  It takes the value of D
• The output Q of a D flip-flop at the next clock cycle is equal to the current D input.


  True
• Match the circuit type with its example:

  Combinational Logic ↔️ AND, OR, NOT gates

  Sequential Logic ↔️ Flip-flops, counters, registers
• What are flip-flops used for in sequential logic circuits?

  Storing a single bit
• Match the flip-flop type with its description:

  D (Data) ↔️ Stores the value of the D input

  T (Toggle) ↔️ Toggles the output between 0 and 1

  JK ↔️ Allows set, reset, or toggle
• State diagrams can be used to design and analyze sequential circuits.

  True
• State diagrams are a powerful tool for understanding and designing sequential logic circuits.


  True
• Match the feature with the type of logic circuit:

  State Dependence ↔️ Sequential Logic

  Clock Signal Not Used ↔️ Combinational Logic
• Flip-flops are used in sequential logic circuits to store a single bit of data.

  True
• Sequential logic circuits use flip-flops to maintain state between clock cycles.


  True
• Flip-flops update their state based on both clock signals and input conditions.


  True
• In a state diagram, each state is represented by a circle or node
• What are the two main uses of state diagrams in sequential circuit design?

  Design and analyze
• Transitions in a state diagram are labeled with the input conditions that cause them.


  True
• Steps to model a sequential circuit using a state diagram

  1️⃣ Identify the states of the circuit

  2️⃣ Represent each state as a node

  3️⃣ Determine the input conditions for transitions

  4️⃣ Draw arrows between states with input labels
• A truth table for a sequential circuit includes inputs, current state, and next state.


  True
• What are the columns in a truth table for a sequential circuit?

  Current state, input, next state
• Digital combination locks use JK flip-flops and logic gates
• What is a key difference between combinational and sequential circuits?

  State dependence