Divided by use, active watt-hour meter, reactive watt-hour meter, maximum demand meter, standard watt-hour meter, multi-rate time-sharing watt-hour meter, prepaid watt-hour meter, loss watt-hour meter, multi-function watt-hour meter and smart watt-hour meter.
② According to the magnitude of the measured voltage classification: divided into voltmeters (basic range for V) and millivoltmeters (basic range for mV). ③ Classification by detection methodThe state period. In the Palace Museum, there is a moire lantern of jade crochets in the Warring States Period, which is also a typical bean-shaped lamp. This lamp is made of Xinjiang Hotan green jade, the lamp plate is round, the surface is smooth, the outer circle is all over the moire, the center of the five-petal flower lamp stand is convex, the lamp post and lamp base are also jade, carved beautifully.
2, 0 since the flourishing of China's neon, neon manufacturing, raw materials and device factories about ten thousand. NEON is derived from the English "NEON", that is, "NEON SIGN", the word "neon" is actually a translation of "neon", and now people"Neon" has been used as a special term.
3, ancient lighting appliances. Pottery and porcelain products are available. The shape is characterized by an oil bowl on the top, a pillar in the middle, a chassis under the plate, and a foot under the plate. There are many forms of lamp posts, such as cylinder shape, spiral shape, animal shape and so on. In the Ming and Qing dynasties, Jingdezhen fired blue and white and painted high foot candlesticks, which were illuminated by candles, so the shape of the lamps changed greatly. A metal spike is attached to hold the candle. The wash type small tray is connected with a long handle, and the middle bearing is connected with a wash type tray and then a high ring foot.
4 years later, has built a number of international standards of the theater, the introduction and establishment of China's ownStage lighting series, the development of China's unique slide performance art. Changes and development of the lamp Changes and development of the lamp 2006-8-3 12:22 Best Answer The development of the lamp physics Professor's bold vision In 1802, in the Petersburg Medical College of Surgery in Russia, a physics professor named Petrov announced that he intended to "use electricity to get light."
6. During the Ming and Qing dynasties, Jingdezhen fired blue and white and painted high-foot candlesticks, which were illuminated by candles, so the shape of the lamps changed greatly. A metal spike is attached to hold the candle. Wash type small tray with long bottomThe handle and the middle bearing are then connected with a washing tray and a high ring foot. In 1809, David, a British chemist, invented the electric arc lamp, and mankind entered the era of using electric lighting. In 1906, Edison invented the household light bulb with tungsten wire as the filament.