What Is a Ballast for in Lights?

Some types of light bulbs available to consumers depend on the use of a ballast to function properly. Ballasts are used to control operating voltage by limiting electrical current flow to the light bulb.

Light Bulbs

Many types of light bulbs including fluorescent bulbs, metal halide bulbs and high-pressure sodium bulbs utilize ballasts. Basically, any gas-discharge light bulb will require the use of a ballast.

Function

Gas-discharge bulbs cannot regulate the amount of electrical current that passes through them. Ballasts are employed to control the operating and starting voltage of these light bulbs.

Types

According to energy.ca.gov, there are different types of ballasts including electronic ballasts and electromagnetic ballasts. Electromagnetic ballasts are being phased out by electronic ballasts; however, extremely high-output light bulbs still employ electromagnetic ballasts.

Flickering

Many light bulbs flicker. This effect is a result from the ballast functioning. Electromagnetic ballasts flicker about 120 times per minute. Electronic ballasts greatly reduce the amount of flicker linked with certain light bulbs, which is one of the reasons they are popular.

Comparisons

Aside from flicker reduction, electronic ballasts offer other benefits compared to electromagnetic ballasts. Electronic ballasts operate quietly and are energy efficient.

References

• The California Energy Commission: Lighting Efficiency Information
• Lighting Research Center: What is a Ballast?
• Light Sources: High Pressure Gaseous Discharge Sources