Definition
In digital electronics, a logic system in which the higher of two voltage levels represents the binary digit 1 (the active or 'true' state), and the lower voltage level represents the binary digit 0 (the inactive or 'false' state).
Plain English
A way of wiring digital circuits where a higher voltage means 'on' or 'yes,' and a lower voltage means 'off' or 'no.'
Context Anchor
Seen in aircraft electrical, avionics, and troubleshooting information when a switch, sensor, warning light, or control unit uses on/off electrical signals.
Derivation
Positive' here means the active or 'true' state is represented by the higher (more positive) voltage. It is called positive because the meaningful signal goes up, not down. The opposite arrangement is called negative logic, where the lower voltage represents the active state.
Why Pilots Care
Modern avionics rely on digital logic. Knowing whether a system uses positive or negative logic matters when troubleshooting, reading schematics, or interpreting signal behavior in aircraft electronic systems.
Intuition Check
Positive does not mean “good” or “confirmed” here. It means the more positive voltage level is the active or ON meaning in that circuit.
Example Sentence 1
The avionics technician confirmed the circuit used positive logic, so a high voltage on the input pin indicated a 'true' signal.
Example Sentence 2
Technicians confirm the board follows positive logic before testing the output signals.