A 12-volt relay is a mechanical or solid-state switch that operates when a 12V electrical signal is applied to its control circuit. The relay typically consists of an electromagnet, a set of contacts, and a spring mechanism. When the 12V is applied to the electromagnet, it generates a magnetic field that attracts the armature, causing the contacts to either close or open, depending on the relay's design. This process allows the relay to control devices that require higher voltages and currents than the control circuit can provide.

    Relays are generally categorized into two types: mechanical relays and solid-state relays (SSRs). Mechanical relays are more common and have moving parts, whereas SSRs rely on semiconductors for switching and are known for being faster and more durable in certain applications.