ESA Certified Alarm Technician Practice Exam

Normally Open switches are used for what type of circuits?

1. Open Loop

2. Closed Loop

3. Switching Circuits

4. Resistance Circuits

The correct answer is: Closed Loop

Normally Open switches are primarily used in open loop circuits. These switches remain in the "off" position until activated, allowing current to flow only when the switch is closed. This is characteristic of open loop control systems, where the output is not fed back to control the input. In an open loop circuit, the action of the switch directly affects the operation of the system — when the switch is closed, the circuit is completed, and the desired effect (such as turning on a light or activating an alarm) occurs. This is distinct from closed loop systems, where feedback is used to adjust the operation based on the output. Closed loop circuits typically utilize normally closed switches or sensors that manage feedback to regulate performance, making them function differently from open loop systems. Thus, the relationship of normally open switches with open loop operations explains why the correct choice pertains to the circuits designed with these types of switches.