Definition
An electronic amplifier circuit that has two inputs and produces an output proportional to the difference between the voltages applied to those two inputs. Signals that are common to both inputs are largely cancelled out, while the difference between them is amplified.
Plain English
A small electronic circuit with two input wires. It looks at the two input voltages, ignores whatever they share, and amplifies only the difference between them.
Context Anchor
Seen in aircraft electronics, avionics, instrument, and autopilot circuit descriptions where a system must compare two electrical signals.
Derivation
Differential comes from the Latin differentia, meaning 'difference.' The name describes exactly what the circuit does: it amplifies the difference between two signals rather than either signal on its own.
Why Pilots Care
It enables precise detection of small signal differences in flight instruments and control systems, supporting accurate attitude and navigation indications.
Intuition Check
Do not read “differential” here as a vehicle-style gear differential or simply as “different.” In this term, it means the circuit responds to the difference between two electrical inputs.
Example Sentence 1
The autopilot computer uses a differential amplifier to compare the commanded heading with the actual heading and produce an error signal that drives the servo.
Example Sentence 2
During autopilot operation the differential amplifier processed the error between commanded and actual heading to adjust the ailerons.