A step-down transformer is an electrical device that reduces voltage from a higher level to a lower level. It consists of two coils of wire, known as the primary and secondary windings. When alternating current flows through the primary winding, it creates a magnetic field that induces a lower voltage in the secondary winding, making it useful for powering devices that require less voltage. These transformers are commonly used in various applications, such as in power distribution systems and electronic devices. By converting high voltage electricity to a safer, lower voltage, step-down transformers help ensure that appliances and equipment operate efficiently and safely.