When talking about lighting, the ballast is the mechanism that stabilizes the electrical current that passes through the fluorescent lamp. The negative differential resistance of fluorescent tubes would cause an ever-increasing flow of current due to the lamp's resistance drops if it wasn't for the ballast regulating that current flow. In fluorescent light fixtures, two common types are electronic ballasts and magnetic ballasts.
If you've ever wondered why some of your fluorescent lamps either flicker or emit a constant buzzing sound, it's due to the type of light ballast used.
Electronic ballasts alter the flow of electricity in the light bulb by using a series of induction coils that are separated from one another. They also change the frequency of the electrical current without changing the voltage. While magnetic ballasts in fluorescent lamps work at a frequency of 60hz, electronic ballasts greatly increase that frequency to 20,000hz.
Due to the very high frequency, you will not see the lights flickering and will not hear a buzzing sound from fluorescent lamps using electronic ballasts.
In contrast to the multiple induction coils on the electronic type, magnetic ballasts only use one single coil. These ballasts can be located inside your light sockets between the plug for the light bulb and the power chord.
In magnetic ballasts, current flows through a coil causing an inductance that is then used to limit and stabilizes the current flowing through a gas lamp with negative resistance properties. In this way, it regulates the current in that only a steady level of alternating current actually flows through the light bulb. The amount of current produced depends on the size of the coil. This alternating flow of the current is what causes the lights of the lamp to flicker and also creates the buzzing sound.
Electronic Ballasts vs. Magnetic Ballasts
Essentially, this contest has already been won. While magnetic ballasts are simple and easy in their design and operating principle, the more sophisticated electronic ballast just has too many advantages.
In addition to not causing fluorescent flicker and noise like magnetic ballasts, electronic ballasts are preferred because they are smaller in size and weigh less. They are also great for the environment and your bank account because they are more energy-efficient and therefore lower your monthly energy bill.
You can also reduce the cost of hiring an electrician to install wire that would be needed for a magnetic control gear. Electronic ballasts can be used as a single ballast in three and four-lamp luminaries.
Another advantage is that electronic ballasts can be used in lamps that are in parallel and series mode. This means that if one of the lamps goes out, this will not affect the other lamps even though all the lamps are using the same ballast.
The current trend, in fact, is that even buildings and people which are already presently using magnetic ballasts, are swapping them out for electronic ones as the replacement process is also very inexpensive.