Which device is an electrically controlled switch used to route electrical power?

• A. Breaker
• B. Relay
• C. PLC
• D. Encoder

Answer: (B)

An electrically controlled switch used to route electrical power is a relay. A relay works by energizing a coil with a control signal, which creates a magnetic field that pulls in or releases contacts to complete or break a circuit, allowing power to flow to a load. This setup lets a small control current switch a larger load current while keeping the control and load circuits electrically isolated. Breakers mainly protect circuits by interrupting current during faults and aren’t used as a controllable routing switch. A PLC is a programmable controller that issues commands to switches or relays but isn’t itself a simple switch. An encoder is a sensor that reports position or speed, not a switching device.