3.4

Logic gates

10 flashcards to master Logic gates

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Key Concept Flip

Draw the truth table for an AND gate.

Answer Flip

An AND gate outputs '1' (TRUE) only if both inputs are '1' (TRUE). Otherwise, the output is '0' (FALSE). The truth table has input columns A and B, and output column Q, with rows: 0 0 0, 0 1 0, 1 0 0, 1 1 1.

Definition Flip

Describe the function of an OR gate.

Answer Flip

An OR gate outputs '1' (TRUE) if at least one of its inputs is '1' (TRUE). It only outputs '0' (FALSE) if all inputs are '0' (FALSE).

Key Concept Flip

What logic gate is represented by the Boolean expression Q = NOT A?

Answer Flip

The Boolean expression Q = NOT A represents a NOT gate. The NOT gate inverts the input; if A is '1', Q is '0', and vice-versa.

Key Concept Flip

Draw the logic gate symbol for a NAND gate.

Answer Flip

A NAND gate symbol is an AND gate symbol followed by a small circle (inversion bubble) at the output. The circle represents the NOT operation.

Definition Flip

Explain the difference between a NOR gate and an OR gate.

Answer Flip

A NOR gate is the inverse of an OR gate. Where an OR gate outputs '1' if any input is '1', a NOR gate outputs '1' only if *all* inputs are '0'.

Key Concept Flip

Create the truth table for a NOT gate.

Answer Flip

A NOT gate takes a single input and inverts it. If the input (A) is '0' (FALSE), the output (Q) is '1' (TRUE). If the input is '1' (TRUE), the output is '0' (FALSE). Truth table has two rows: 0 1, 1 0

Definition Flip

Define the term 'logic gate'.

Answer Flip

A logic gate is an elementary building block of a digital circuit. It takes one or more binary inputs (0 or 1) and produces a single binary output based on a logical operation.

Definition Flip

What is a 'truth table' used for in the context of logic gates?

Answer Flip

A truth table is a table that shows all possible combinations of inputs to a logic gate (or circuit) and the corresponding output for each combination. It completely defines the behavior of the gate.

Key Concept Flip

Write the Boolean expression for a NOR gate with inputs A and B and output Q.

Answer Flip

The Boolean expression for a NOR gate with inputs A and B and output Q is: Q = NOT (A OR B).

Definition Flip

Describe how a logic circuit can be created from logic gates.

Answer Flip

A logic circuit is formed by connecting multiple logic gates together, where the output of one or more gates can be used as the input to other gates, implementing more complex logical functions.

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3.3 Memory and storage 4.1 Types of software

Key Questions: Logic gates

Describe the function of an OR gate.

An OR gate outputs '1' (TRUE) if at least one of its inputs is '1' (TRUE). It only outputs '0' (FALSE) if all inputs are '0' (FALSE).

Explain the difference between a NOR gate and an OR gate.

A NOR gate is the inverse of an OR gate. Where an OR gate outputs '1' if any input is '1', a NOR gate outputs '1' only if *all* inputs are '0'.

Define the term 'logic gate'.

A logic gate is an elementary building block of a digital circuit. It takes one or more binary inputs (0 or 1) and produces a single binary output based on a logical operation.

What is a 'truth table' used for in the context of logic gates?

A truth table is a table that shows all possible combinations of inputs to a logic gate (or circuit) and the corresponding output for each combination. It completely defines the behavior of the gate.

Describe how a logic circuit can be created from logic gates.

A logic circuit is formed by connecting multiple logic gates together, where the output of one or more gates can be used as the input to other gates, implementing more complex logical functions.

About Logic gates (3.4)

These 10 flashcards cover everything you need to know about Logic gates for your Cambridge IGCSE Computer Science (0478) exam. Each card is designed based on the official syllabus requirements.

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