Definition
An electronic circuit whose output at any moment represents the accumulated total of its input over time. Rather than reporting the instantaneous value of a signal, an integrating circuit continuously sums the input, so the output reflects how much has occurred from the start of measurement to the present.
Plain English
A circuit that adds up an input signal as it happens and gives you the running total. If the input is a rate, the output is the total amount that rate has produced so far.
Context Anchor
Seen in avionics, autopilot, and aircraft instrument discussions where electrical signals are shaped, smoothed, or used to build a correction over time.
Derivation
From the Latin integrare, meaning 'to make whole.' In mathematics, integration is the process of summing many small pieces to get a total. An integrating circuit performs this summing electronically.
Why Pilots Care
Several cockpit displays rely on integrating circuits behind the scenes. A fuel totalizer integrates fuel flow over time to show fuel used; an inertial system integrates acceleration to produce velocity. Knowing this helps a pilot understand why these readings drift if the input signal is slightly off — small errors accumulate.
Analogy
It is like keeping a running total instead of looking at one single number. One small change may not matter much by itself, but many small changes added over time can produce a larger result.
Intuition Check
Integrating does not mean combining several aircraft systems into one unit here. It means adding an electrical signal over time.
Example Sentence 1
The fuel totalizer uses an integrating circuit to convert fuel flow into total fuel burned since engine start.
Example Sentence 2
Technicians traced the erratic altitude hold to a failing integrating circuit in the flight director computer.