What is an electric circuit that energizes signaling equipment called?

An electric circuit that energizes signaling equipment is commonly referred to as a signal circuit. This terminology is used in electrical code and practice as it specifically describes the function of the circuit, which is to transmit signals to devices designed to alert users or operators, such as alarms, bells, or indicators.

In the context of electrical systems, a signal circuit is characterized by its role in producing a meaningful electrical signal that can activate the signaling equipment. This definition aligns closely with the function of the circuits used in various applications, including fire alarm systems and other emergency notification systems, where signaling is crucial for safety and communication.

Other terms listed, such as alert circuit, notification circuit, and indicator circuit, may describe similar concepts but do not specifically encapsulate the functionality of energizing signaling equipment as directly as the term "signal circuit." Each of these terms may have slightly different connotations or applications but do not serve as the standard designation for an electric circuit primarily focused on signaling.