Some areas covered include developing an understanding of simple, open, and closed circuits and learning how different mechanical systems work.
一些简单的开、闭合电路，可以让孩子们掌握机械系统的工作原理。
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
The chip has internal short circuit protection, open circuit protection, lightning strike protection and thermal shutdown protection circuits.