Fluorescent starters are used in several types of fluorescent lights. The starter is to help the lamp light. When voltage is applied to the fluorescent lamp, the starter allows current to flow through the filaments at the ends of the tube. The current causes the starter’s contacts to heat up and open, thus interrupting the flow of current. The tube lights. Since the lighted fluorescent tube has a low resistance, the ballast now serves as a current limiter.
A magnetic ballast uses coiled wire and creates magnetic fields to transform voltage. A magnetic ballast does not change the frequency of the power to the lamp—it remains the same as the input power.
A capacitor is an electrical device that can store energy in the electric field between a pair of closely-spaced conductors (called ‘plates’). When voltage is applied to the capacitor, electric charges of equal magnitude, but opposite polarity, build up on each plate.