Which of the following is a basic component of burglar alarm systems?

• A. Sensing devices
• B. Input device
• C. Output display
• D. Password

Answer: (A)

Detecting an intrusion is what a burglar alarm system is built to do, and that happens through sensing devices. These are the parts that actually monitor the protected area—door and window contacts that sense openings and motion detectors that sense movement inside. They continuously watch for changes and send alerts to the control panel to trigger alarms. Without sensing devices, nothing in the system can detect a breach, so they are the essential, basic component.

Input devices like keypads are used to arm, disarm, or configure the system, but they don’t detect intrusions on their own. Output displays or alarms inform people of an alert, but they rely on sensing devices to know when to activate. A password serves as an access control measure, not a physical part that detects or signals an intrusion.