Why tube lights save more electricity than bulbs filament lamp?
A 40-watt tube light looks as bright as a 150-watt filament bulb, but it consumes less electricity than a filament lamp. It also means that a tube light’s luminous efficiency is higher than that of an incandescent lamp, making it more energy-efficient than incandescent lamps. Why is that?
The main reason is that the mode of light of the tube light and the filament is different. Incandescent lamps rely on the heat effect produced when an electric current is passed through the filament to glow. Any object that is heated to 525 ° C or higher will glow. Besides, the luminous effect follows the increase in temperature that increases. Therefore, people often choose to use tungsten wire with a high melting point (3410 ° C) to make filament. Despite the continuous improvement, the incandescent lamp’s luminous effect has been enhanced. However, the amount of electricity it converts into optical energy is still minimal. Most of the electricity is still converted to heat, which is wasted in vain.
The luminescence principle of tube lights is different. Inside its tube is coated with fluorescent material, two ends with electrodes, in the tube filled with acid gas and a little mercury. When an electric current is passed through, the electrode emits electrons, which move at extremely high speed to the other end of the tube. Along the way, when they collide with the argon molecules, more electrons will be released.
Crowded electrons collide with the mercury vapor molecules, causing the mercury vapor molecule to gain an irregular energy yield and jump to a relatively high energy state. When these molecules return from the high energy state to the normal energy state, they emit excess energy in the ultraviolet mode. Ultraviolet rays cannot be seen, but after the fluorescent material absorbs it on the lamp tube wall, the fluorescent material emits visible light. Therefore, it can be said that very little heat is generated during the light of a tube light; the light it emits is a kind of cold light. That makes the luminous efficiency of the tube light much improved, saving more energy than incandescent lamps.
Due to the cessation of luminous discharge, the stretching head gradually cools, then restored to its original shape. When it separates from the fixed end, the circuit breaks off, cutting off the current. When the current is cut off, on the ballast inducing a very high voltage, it can reach 1000 volts. Together with the input source voltage, it is applied to the two electrodes of the lamp tube. So the tube light came on.
If the process mentioned above happens once and cannot turn on the tube light, the neon tube in the starter will light again and then turn off, then light again, repeating like a few times. We can see the starter blink continuously until the tube light turns on. After the tube light is completely on, the current increases very quickly, the instant ballast has the effect of limiting the input current to within the specified range. Simultaneously, the mercury in the lamp tube evaporates, the resistance between the two electrode ends is greatly reduced, so the voltage at both ends is also low. So the starter ceases to generate luminous discharges and does not light up either. Mercury vapor, which causes the mercury vapor molecule to gain an extraneous energy yield, jumps to a relatively high energy state. When these molecules return from the high energy state to the normal energy state, they emit excess energy in the ultraviolet mode. Ultraviolet rays cannot be seen, but after the fluorescent material absorbs it on the lamp tube wall, the fluorescent material emits visible light. Therefore, it can be said that very little heat is generated during the light of a tube light; the light it emits is a kind of cold light. That makes the luminous efficiency of the tube light much improved, saving more energy than incandescent lamps.
Different fluorescent substances can emit light of different frequencies, which exhibits different colored light in our eyes. If an appropriate luminescent is selected, the tube light can be very close to sunlight.
The firefly can also glow; the light emitted is also cold. Also, fireflies have much higher luminous efficacy than tube lights. How to learn in this animal, take a step to improve luminous efficiency is a problem that scientists find very interesting.