What type of switch is represented by component 3 in figure T-2?

In schematic diagram T-2, component 3 represents a basic on/off switch. It has one moving part (the pole) that connects to one stationary contact (the throw) to complete the circuit. This makes it a Single-Pole Single-Throw (SPST) switch. Distractors like double-pole or double-throw are incorrect because double-pole switches would have two moving elements controlling two separate circuits simultaneously, and double-throw switches would route one input to two different possible outputs. The symbol shown simply breaks or connects a single line.