What triggers the Switch Mode Power Supply (SMPS) to activate?

• A. Activation- when power is lost/batteries used; sensor will alert that no other alarms will work without A/C power
• B. Activation- when power is restored
• C. Activation- when motion is detected
• D. Activation- when a door opens

Answer: (A)

Switching to battery power when the main AC supply fails is what the SMPS is designed to do. When power is lost, the SMPS activates to draw from the onboard batteries so alarms and sensors keep operating without interruption. Once AC power returns, it switches back to the wall supply. Events like motion or a door opening are sensor-triggered actions, not power-status changes, so they don’t cause the power supply to activate.