Definition
A computing device that represents data using continuously variable physical quantities — such as voltage, fluid pressure, or mechanical rotation — rather than discrete numerical values. The output varies smoothly and proportionally with changes in the input, making it well suited for measuring and responding to real-world signals like airspeed, altitude, or fuel flow.
Plain English
A device that handles information by using something that changes smoothly — like a moving needle, a turning shaft, or a rising voltage — instead of using numbers. The reading goes up and down in step with whatever it is measuring.
Context Anchor
Seen in discussions of older aircraft instruments, autopilots, engine controls, and other systems that process changing aircraft data.
Derivation
‘Analog’ comes from the Greek analogos, meaning ‘proportionate’ or ‘corresponding.’ The device is called analog because its internal signal is an analog — a proportional copy — of the real-world quantity it represents.
Why Pilots Care
Pilots and technicians working on older aircraft must understand analog computers to troubleshoot continuous-signal systems in navigation and flight controls.
Analogy
Think of the volume knob on an old radio. As you turn it, the sound rises smoothly through every level in between. That smooth, proportional response is how an analog computer handles information.
Intuition Check
Analog does not just mean old-fashioned here. It means the computer works with smooth, continuous changes rather than separate digital numbers.
Example Sentence 1
The fuel flow gauge in the older trainer is driven by an analog computer that converts pressure into a continuous needle reading.
Example Sentence 2
During preflight the technician verified the analog computer output by monitoring smooth needle movement on the indicator.