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Interested in this product? Get Best Quote. Yes, I am interested! Features Metal case design with good thermal performance and high reliability High power factor 0. For the best experience on our site, be sure to turn on Javascript in your browser. A fluorescent tube uses electricity to make mercury gas emit ultraviolet UV light. When that UV light which is invisible to the naked eye interacts with the coating of phosphor powder inside the tube, it glows and produces the light we see and use in our homes.
But whenever we use electricity we must control it, otherwise we risk destroying the device and even putting ourselves in danger. The process that occurs inside a fluorescent light involves molecules of mercury gas being heated by electricity and made more conductive.
Without a ballast to control this, there would be too much current for the light to take, and it would burn out and possibly even catch fire. Fluorescent lights use either an electronic or a magnetic ballast. These rely on the principles of electromagnetism, in that when an electrical current travels through a wire, it naturally generates a magnetic force around itself.
A magnetic ballast also called a choke contains a coil of copper wire. The magnetic field produced by the wire traps most of the current so only the right amount gets through to the fluorescent light. That amount can fluctuate depending on the thickness and length of the copper wire. This small cylinder-shaped component sits behind the light fixture and is filled with gas which, when heated, enables the light to start.
This is called the pre-heat method. As it can take several seconds for this process to complete, you may see a delay between the moment you flick the switch and when the fluorescent light begins to glow. Used in older T12 and some T8 tubes, this method functions without a starter. One advantage of the rapid-start method is that by providing a low, continuous current rather than a strong surge, it prolongs the life of the fluorescent light.
However, it does use more energy. Using more sophisticated circuitry and components, ballasts can control the current running through fluorescent lights with greater precision.
Some older electronic ballasts employ the rapid-start method described above, while newer and more advanced models use what are known as instant-start and programmed-start. These ballasts were developed so lights could be turned on and operated at their brightest at the first flick of the switch. Rather than pre-heat the electrodes, the ballast uses a high-voltage boost around volts to heat and light the filaments and then the mercury gas.
Designed for areas in which the lights are constantly switched on and off, these ballasts pre-heat the electrodes with controlled amounts of current before applying a higher voltage to start the light. The basic construction of a typical electronic ballast involves a low-pass filter, rectifier, buffer capacitor and a high frequency oscillator as shown in the figure below.
This converter also contains the buffer capacitor, which is charged with a DC voltage. In the high frequency HF power generator, this DC voltage is transformed into a HF voltage, which provides the power for the lamp controller. The ballast controller determines all these functions. Block diagram indicating main functions of electronic ballast. The ballast takes advantage of a characteristic of fluorescent lamp whereby greater luminous efficacy please click for definition is obtained at high operating frequency above 20kHz.
Ballast losses are reduced compared to conventional ballast, as the solid state circuit contains no copper windings. In addition, with less heat generated to the indoor space, the cooling load on air conditioning equipment will also be reduced. How to cite. Definition Device s in the electric lamp circuit of gas discharge and solid-state lamps which limits the lamp current to the required value and ensures that the lamp can be started and once started can be operated stably over a longer period.
Igniters for Fluorescent Lamps In most fluorescent lamp circuits, the electrodes are preheated for a few seconds before a high-voltage peak is applied across the lamp to initiate the discharge. This is a preview of subscription content, log in to check access. Wout van Bommel 1 Email author 1.
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