Final answer:
In aircraft electrical systems, automatic reset circuit breakers serve as protective automatic switches that open under excessive current and can reset themselves. They are crucial for safety during flight, and for large voltage systems, may use insulating gas to control sparking.
Step-by-step explanation:
Circuit breakers are critical components in aircraft electrical systems, serving as automatic switches that protect circuits by opening when sustained current exceeds certain limits. In the context of an aircraft, an automatic reset circuit breaker is designed to interrupt the circuit and prevent damage or fire if an overcurrent situation occurs. Afterwards, it can automatically reset itself, restoring the circuit when the situation is safe again. This feature is particularly important in aircraft systems where manual resetting may not be possible or practical during flight.
A specific type of circuit breaker that may be used in aircraft is a bimetallic strip circuit breaker. It operates using a bimetallic strip that bends when heated by excess current, tripping the breaker and opening the circuit. Once the strip cools, the breaker can reset itself. Another form of protection is the ground fault circuit interrupter (GFCI), which protects against electric shock by quickly responding to changes in current.
In the case of large voltages and currents, such as those found in power-distribution systems, circuit breakers may employ insulating gas or gas jets to extinguish any sparks that occur when high-voltage electricity is interrupted. AC current is considered safer in this context, as it provides more frequent opportunities to extinguish arcs due to the current going through zero multiple times per second.