Definition
An electronic circuit built from logic gates (such as AND, OR, and NOT) that produces a specific output signal based on the combination of input signals it receives. Logic circuits operate on binary states -- typically represented as on/off, high/low, or 1/0 -- and are the foundation of digital systems used in modern avionics, computers, and flight control equipment.
Plain English
A small electronic circuit that takes one or more on/off signals coming in and produces an on/off signal going out, based on a fixed set of rules. It's the basic building block of any digital electronic system.
Context Anchor
Seen in aircraft electrical systems, avionics, warning systems, and automatic control systems.
Derivation
From the Greek 'logikos' (reasoning) and the Latin 'circuitus' (a going around). The name reflects that the circuit performs simple reasoning steps -- if this AND that, then output -- using flowing electrical signals.
Why Pilots Care
These circuits run autopilot logic, fuel shutoff decisions, and many warning lights, so a fault can produce incorrect system behavior.
Analogy
Think of a logic circuit as a light switch that only turns on when two specific switches are both flipped up. The rule is fixed; the output depends entirely on the inputs.
Intuition Check
Logic circuit does not mean a circuit that “thinks” like a person. It means an electronic circuit built to follow fixed yes/no rules.
Example Sentence 1
The autopilot's disconnect warning is triggered by a logic circuit that monitors several inputs at once.
Example Sentence 2
A failed logic circuit in the annunciator panel turned on the low-fuel light even though tanks were full.