The typical traffic signal controller assembly is powered by what type of electrical current?

The typical traffic signal controller assembly operates using 120 volts AC power. This is commonly used in traffic signal systems because it is standard in many electrical systems for buildings and infrastructure. The use of alternating current (AC) allows for efficient transmission of electricity over distances, which is necessary for the widespread deployment of traffic signals.

Traffic signal controllers require a stable and reliable power supply, and 120 volts AC meets these criteria. This voltage level is sufficient to power the various components found within the controller, enabling it to manage the signal lights and communicate with other devices in the traffic system. The choice of 120 volts AC also aligns with safety standards, making it easier to integrate the controllers into existing electrical systems.

In contrast, other options present different voltage levels or types of current that are either not standard for traffic signal systems or not suitable due to technical or safety reasons. For example, 48 volts DC and 12 volts DC may be used in specific smaller or battery-operated devices, but they are not typical for full traffic signal controllers which require more robust power. 240 volts AC, while used in industrial applications, is generally not employed in traffic signal systems due to safety and infrastructure considerations.