On what principle do electric relays operate?

Electric relays operate on the principle of electromagnetism. When a current flows through the coil of the relay, it generates a magnetic field due to the electromagnetic effect. This magnetic field attracts a movable armature, which then either opens or closes a set of contacts, effectively controlling the electrical circuit connected to the relay.

The core operation relies on the interaction between electricity and magnetism, where a small input signal can control a larger output signal. This mechanism is fundamental in electrical systems as it allows for the switching of electrical circuits without requiring a mechanical connection, making relays essential for automation and control in various applications.

Understanding this principle is crucial because it emphasizes the relay's role in isolating different sections of a circuit and its use in controlling devices with higher power demands safely.