NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

What function does a ballast serve in a lighting system?

1. Start the lamp

2. Control the current

3. Both start the lamp and control the current

4. None of the above

The correct answer is: Both start the lamp and control the current

The function of a ballast in a lighting system is multifaceted, primarily designed to start the lamp and control the current flowing through it. When a lamp, particularly a fluorescent or HID (High-Intensity Discharge) lamp, is first powered on, the ballast generates a high voltage to initiate the arc between the electrodes, effectively starting the lamp. Once the lamp is lit, the ballast regulates the current to ensure that it stays within safe operating limits. This is crucial because without proper current regulation, the lamp could draw too much electricity, leading to overheating or damage. Thus, the ballast effectively prevents potential failures by controlling the electrical environment throughout the operation of the lamp. This combined functionality—starting the lamp and regulating power—highlights the significance of the ballast in a lighting system, making it an indispensable component for maintaining the efficiency and longevity of the lighting source.