What type of device acts as a circuit breaker that trips with a shunt?

The shunt trip circuit breaker operates by using an electromagnetic mechanism that allows it to disconnect the electrical circuit when a specific condition occurs, such as an overcurrent or fault. This device is designed to trip remotely via an external control signal, which is sent through a shunt trip coil. When the coil is energized, it activates the mechanism to open the circuit, effectively acting as a circuit breaker.

This functionality makes shunt trip circuit breakers unique compared to other devices. For instance, while fuses provide overcurrent protection by melting and disconnecting the circuit, they do not have a remote tripping mechanism. Plug type relays and diodes serve different purposes in electrical circuits, such as controlling current flow and directing it respectively, but they do not provide the same circuit breaking and remote disconnect functionalities that a shunt trip circuit breaker offers.

Thus, the ability of the shunt trip circuit breaker to act on an external command is what makes it the correct answer for this question, as it clearly defines its role as a device that can trip and disconnect a circuit with precision and control.