Which device is an example of overcurrent protection?

Overcurrent protection is a critical aspect of electrical systems designed to prevent damage caused by excessive current flow, which can occur due to short circuits, overloads, or equipment failures. A fuse serves this purpose effectively by interrupting the current flow when it exceeds a predetermined level.

When the current rises above the fuse's rated capacity, the heat generated causes the fuse element to melt, creating an open circuit that stops the flow of electricity. This protects downstream devices and wiring from overheating and potential failure. Such devices are crucial in maintaining safety and reliability in electrical systems.

In contrast, devices like transformers, switches, and relays do not directly provide overcurrent protection. A transformer is used to convert voltage levels, a switch controls the flow of current but does not inherently protect against overcurrent, and a relay typically serves as a control mechanism rather than a protective device. Therefore, the fuse is the clear choice as an example of overcurrent protection.