Which of the following is a characteristic of a knife switch?

A knife switch is characterized by its manual operation, which allows users to control the circuit by physically moving a lever or blade to open or close the circuit. This design facilitates a clear visual indication of whether the circuit is on or off, making it easy to operate and ensuring safety during maintenance or troubleshooting.

The manual operation feature is significant as it allows for straightforward emergency shut-off capabilities and reliable toggling between states, which can be vital in various applications. While knife switches can be used in high voltage circuits, they are not exclusive to such applications, and their functionality is dependent on manual input rather than automation or regulation of current.

In terms of design, knife switches do include moving parts; specifically, the blade that pivots to connect or disconnect the circuit. Therefore, the characteristic of being manually operated effectively describes what sets knife switches apart from other types of switches, which may be automated or lack the same level of tactile feedback and visibility of operation.