How to check the quality of fluorescent lamps with a multimeter
How to use a multimeter to detect fluorescent lamps
How are the four pins of an ordinary fluorescent tube (light bar) connected internally, what is its working principle, and how to use a multimeter to judge the quality of the fluorescent lamp,
There is a small piece of filament at each end of an ordinary fluorescent tube, and the two feet at each end of a good tube are connected when measured with a multimeter, and there is only a small cold resistance.
Let’s take a look at the working principle of fluorescent lamps. During manufacture, a small drop of mercury (mercury) is filled in the lamp tube after being evacuated, and the tube wall is coated with fluorescent powder. When the lamp tube is started, after the filaments at both ends are heated, the mercury It evaporates into a gas, and the gas is ionized to conduct electricity into a loop. At the same time, the gas emits a large amount of ultraviolet rays, and the ultraviolet rays excite the phosphors to emit visible light. In addition, when the lamp tube is aged, the filaments at both ends evaporate and lead to blackening at both ends of the lamp tube. Even if the filament is not broken, the lamp tube cannot be used. This kind of lamp tube is difficult to start.
If you just judge whether the lamp is broken, it is relatively simple. Let's see how to judge the overall quality of the lamp.
How to check the quality of fluorescent lamps with a multimeter
1. Use an electroscope to measure point L. If the electroscope does not light up, the live wire is not connected.
2. Use a test pen to measure point A (ballast to lamp pin), if the test pen does not light up, the ballast is broken.
3. Use a test pen to measure point B. If the test pen does not light up, the filaments of A and B are broken.
4. Short circuit B and C (both ends of the starter). If the filament is not on, the D and C filaments are broken; if it is on, the starter is broken.
5. Use an electroscope to measure N points. If the electroscope is on, the zero line is broken.
