Definition
A circuit breaker that opens to interrupt current flow when an overload occurs and then automatically closes again to restore the circuit after a short cooling period, without requiring manual action by the pilot or crew.
Plain English
A safety switch that cuts off the electrical flow when too much current passes through it, then resets itself once it has cooled down so the circuit can work again.
Context Anchor
Seen in aircraft electrical system descriptions, wiring diagrams, and maintenance discussions.
Derivation
Automatic comes from a Greek word meaning self-acting. Reset means to set something back again. Breaker refers to a device that breaks, or opens, an electrical path. Together, the words point to a breaker that opens the circuit and then sets itself back without a person pushing it.
Why Pilots Care
Provides uninterrupted power to essential systems during transient faults while still protecting circuits, but repeated trips signal an underlying problem that must be investigated.
Analogy
It is like a safety switch that turns itself back on after it cools down. If the same overload is still there, it turns off again.
Intuition Check
Do not assume “automatic-reset” means “automatically repaired.” It only means the breaker closes again by itself; the original electrical problem may still exist.
Example Sentence 1
The landing light circuit used an automatic-reset circuit breaker, so the light flickered back on a few seconds after the brief overload cleared.
Example Sentence 2
During preflight inspection the mechanic noted the automatic-reset circuit breaker had cycled and verified the wiring for any persistent fault.