Opencircuits are more likely to occur at the connector ends.
电路开路更可能发生在连接器端。
2
Relays are the logic elements of a protection system which sense the fault and cause the circuit-breaker trip circuits to be energized and the breakers to open their contacts.
继电器是保护系统的逻辑元件，它感知故障，并使断路器解扣电路带电和断路器打开触点。
3
Some areas covered include developing an understanding of simple, open, and closed circuits and learning how different mechanical systems work.