How does the selection of the ballast choose the ballast

Answer:

Listen to the sound, see if the light is bright and stable, and the frequency is not visible to the naked eye. Basically see in what ways do you use, the ordinary household no problem, but work and study with will buy brand, high frequency as far as possible, which help to protect your vision, but also not for a long time under the lights, have to at least one hour to rest more than ten minutes

The characteristic curve of a high-pressure sodium lamp High pressure sodium lamp light power and light voltage curve is called modulation characteristic curve, the linear relationship between the characteristic curve for a specific lights, can pass within a certain range to change the power supply voltage or ballast impedance, which changes the voltage and the power of the light, as shown in figure 1. When the lamp voltage is equal to the design voltage, the lamp power will meet the design target power. For the same type, the same power lamp has a similar characteristic curve, as shown in figure 2. For those lamps with high voltage, the slope of the slope of the characteristic curve decreases. The characteristic curve of a high-pressure sodium lamp ballast When the high-pressure sodium lamp works continuously under constant input voltage, the change of the lamp voltage and the lamp power will follow the characteristic curve of the ballast. The characteristic curves of two typical ballast are shown in figure 3. The curve can be measured by a batch with different characteristic curve of light the lamp voltage and light power, or by external methods for the same lamp, make the cold end temperature rise of the discharge pipe to change the lamp voltage and lamp power. A set of ballast characteristic curves can be obtained when the power voltage changes. The influence of the ballast characteristic curve is shown in figure 4 for the voltage increase or decrease of the rated power supply.

High-pressure sodium lamps and ballast High pressure sodium lamp and high pressure mercury lamp in performance is different, not only mercury search within high pressure sodium lamp, also filled with sodium, during the lamp work, sodium and mercury in the form of liquid sodium mercury gas storage in the cold end section of the discharge tube. During the lifetime of a high-pressure sodium lamp, the power of the lamp changes as the voltage of the lamp changes. This situation is different and high pressure mercury lamp, high pressure mercury lamp in power changes lamp voltage is relatively stable, because high pressure mercury lamp light while working inside the mercury vapor pressure in saturated condition. The relationship between the voltage of the lamp and the power of the lamp is based on the excess of sodium mercury in the discharge tube. During the lamp work, only part of the mercury and sodium vapor pressure, vapor pressure also is reflected in the light of high and low voltage, it depends on the discharge tube "cold end temperature. The change of the temperature of the cold end result in the change of the vapor pressure, the change of the lamp voltage, and the change of the power of the lamp. The relationship between lamp voltage and lamp power in a certain power range is approximately linear

The HID lamp's choice of the ballast and the working circuit Shen jiping: December 28, 2006, at 19:56 HID lamp is a kind of high pressure discharge, the discharge of the negative resistance characteristics of "FuYiAn" performance, so the lamp circuit must be connected to the flow of work device, which is often referred to as ballast. The HID lamp is most of the work in the communication state, using the reactance device as the ballast. HID lamp has different types, according to the type of lamp and application requirements, different types of ballast circuit can be configured, the best match for ballast circuit and a lamp. The commonly used HID lamp is a high pressure mercury lamp, high voltage sodium lamp and gold halogen lamp. The high voltage mercury lamp is the earliest source of light in HID lamp, the product is stable, and the associated ballast circuit is more mature. The high voltage sodium lamp and the gold halogen lamp are the new light source of high efficiency and energy saving in modern times, and the ballast can be matched with the lamp to achieve a better overall effect.

The quadrangle of a high-pressure sodium lamp ballast In the use of high pressure sodium lamp system exists the change of various factors, such as: the change of the power supply voltage, lamp performance changes over time, the efficiency of the internal reflector lamps and lanterns, using the environment changes, etc., how to make characteristic curve to adapt to the dynamic changes of the ballast? High pressure sodium lamp of international standards, in the form of boundary figure, ballast can ensure that the lamp life during the dynamic conditions, and any change its electric performance parameters of the limit in a certain range. As shown in figure 5, the high-pressure sodium lamp specifies a quadrilateral graph for the ballast characteristic curve. The upper part of the quadrangle represents the maximum power of the high-pressure sodium lamp. The maximum power limit depends on the maximum allowable temperature of the discharge tube. The maximum power line is usually set at 20-30% of the bulb's nominal power. The lower part of the quadrangle represents the limit of the minimum power of a high-pressure sodium lamp. Set the minimum power line to ensure that the light bulb's heating properties, the stability of the bulb's work, the output efficiency of the acceptable light, and the performance of the light color are also available. The minimum power lines are usually set near 20-30% below the nominal power.