🔍 Key Concepts

• Electrical relay basic purpose and how it operates (electromagnet controlling contacts) • Difference between protective devices (like fuses or current limiters) and switching devices • How circuits are controlled locally vs. remotely using low power to control higher power

💭 Think About

• Ask yourself: What is the primary job of a relay in a circuit—does it mainly protect from too much current, provide many voltages, process audio, or open/close a circuit? • Think about how you can turn a large motor or high‑power circuit on and off from a small control switch—what component does that? • Which option best matches a device that uses a small control current to control a larger current in another part of the circuit?

✅ Before You Answer

• Verify which choice best describes a switch operated by an electromagnet rather than a protective or signal‑processing device. • Eliminate any choices that describe current limiting or voltage supply functions—that is not the main role of a relay. • Confirm which option clearly involves control from a distance or separate control circuit, which is how relays are often used on vessels.