AND gates are like security doors that need BOTH a keycard AND a fingerprint. Only when ALL inputs are 1 (true) does the output become 1. It's the strictest gate - everything must be true.
OR gates are like motion sensors that trigger if EITHER the door sensor OR the window sensor detects movement. If ANY input is 1 (true), the output is 1. At least one condition must be met.
NOT gates are inverters - they flip the signal. If the input is 0, output is 1. If input is 1, output is 0. Think of it as a "do the opposite" gate.
Why this matters: Every single computation in your computer - from calculating 2+2 to rendering 3D graphics - ultimately comes down to billions of these simple gates making binary decisions at lightning speed.
This deep dive covers Deep Dive: The Three Basic Logic Gates within Logic Gates for GCSE Computer Science. Revise Logic Gates in 3.4 Computer Systems for GCSE Computer Science with 16 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 9 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Logic Gates
An AND gate has inputs A=1 and B=0. What is the output?
Complete the truth table for an OR gate with two inputs A and B. | A | B | Output | |---|---|--------| | 0 | 0 | | | 0 | 1 | | | 1 | 0 | | | 1 | 1 | |