A Single Pole Double Throw (SPDT) switch is an electrical component that allows a single input to connect to one of two outputs. It has three terminals: one common terminal and two output terminals. When the switch is toggled, it connects the common terminal to either of the two outputs, enabling control over multiple circuits or devices. SPDT switches are commonly used in various applications, such as in lighting systems or electronic devices. They can help manage power distribution, allowing users to choose between different operational modes or routes for electrical current. This versatility makes SPDT switches essential in many electrical and electronic setups.