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Digital Electronics and Logic Gates

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What do the AND, OR and NOT gates do, and how is each one described by its truth table and Boolean expression?

State the function, symbol, truth table and Boolean expression of the AND, OR and NOT logic gates
A focused answer to the O-Level Electronics outcome on the basic logic gates. The AND, OR and NOT gates with their symbols, truth tables and Boolean expressions.
8 min answer →

What does it mean for a signal to be digital, and how do binary numbers and the two logic levels represent information?

Describe digital logic levels, explain binary representation, and convert between small binary and denary numbers
A focused answer to the O-Level Electronics outcome on digital signals. Logic 0 and 1, why two levels are robust, binary place values, and converting between binary and denary numbers.
8 min answer →

How do we design a logic circuit that does a real job, starting from a description of when the output should be on?

Design a simple logic system from a written specification by building its truth table and selecting the gates needed
A focused answer to the O-Level Electronics outcome on designing logic systems. Turning a written specification into a truth table, a Boolean expression and a gate circuit.
9 min answer →

What do the NAND and NOR gates do, and why is the NAND gate called a universal gate?

State the function, truth table and Boolean expression of the NAND and NOR gates and explain why NAND is universal
A focused answer to the O-Level Electronics outcome on NAND and NOR gates. Their truth tables and Boolean expressions as inverted AND and OR, and why NAND is a universal gate.
8 min answer →

How do we work out the output of several logic gates connected together, for every possible combination of inputs?

Derive the truth table of a combinational logic circuit built from two or more gates and write its Boolean expression
A focused answer to the O-Level Electronics outcome on combinational logic. Building the truth table of a multi-gate circuit step by step and writing its Boolean expression.
9 min answer →