Final answer:
When the agent discharge switch is actuated, it completes a circuit that applies voltage to a pyrotechnic squib, which initiates the release of the fire extinguishing agent.
Step-by-step explanation:
When the agent discharge switch is actuated, an electric circuit is completed and voltage applied to the pyrotechnic squib. This device is integral to various fire suppression systems. The squib, when energized, ignites a small amount of explosive material, which then opens the container, typically a bottle, that holds the extinguishing agent under pressure. Upon activation, the agent is released to extinguish the fire. The squib is a critical component as it provides the initial action that releases the extinguishing agent in a timely manner during emergency situations.