Class 0 luminaires are luminaires that rely on basic insulation as protection against electric shock. This means that the accessible conductive parts of the luminaire (if such parts) are not connected to the protective conductors in the fixed line of the facility, and once the basic insulation fails, it has to rely on the environment. Class 0 luminaires provide protection against electric shock only under basic conditions, and provide protection against electric shock under fault conditions (ie, when insulation fails). Class 0 luminaires have not been allowed for wiring rules in CENELEC countries in Europe. These countries are Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Ireland, Norway, Sweden and the United Kingdom. In addition to the special equipment known as "isolation devices" in Italy, the wiring rules do not allow the use of Class 0 lamps. In Japan, Class 0 lamps are only allowed for power supply voltages from 100 to 127V. (2) Class I tools Class I lamps mean that the lamp's protection against electric shock not only relies on basic insulation, but also includes additional safety measures, that is, connecting the accessible conductive parts to the protective earthing conductors in the fixed line of the facility, so that Accessible conductive parts are not energized when the basic insulation fails. Class I luminaires provide protection against electric shock under normal conditions by relying on basic insulation. Under fault conditions (ie, when insulation fails), they are connected to the protective earthing conductors in the fixed line of the facility by means of accessible conductive parts to provide protection against electric shock. Class I luminaires can be either double insulated or reinforced, or have special low voltage (SELV) powered components. (3) Class II tools Class II lamps mean that the protection against electric shock not only relies on basic insulation, but also has additional safety measures, such as double insulation or reinforced insulation, but there is no protective grounding measures or installation conditions. Class II luminaires provide protection against electric shock under normal conditions by relying on basic insulation. Under fault conditions (ie, when insulation fails), additional insulation or reinforced insulation is provided to provide protection against electric shock. Class II luminaires may have components that are safely powered by extra low voltages, but may not have grounded components. (4) Class III lamps Class III lamps refer to lamps that are protected against electric shock by relying on the power supply voltage as a safety extra low voltage and that do not produce a voltage higher than the safety extra low voltage. Class III luminaires should not provide protective grounding. In summary, Class 0 lamps are less secure than Class I, Class II, and Class III lamps. Imagine a movable luminaire with a Class 0 metal casing. Once the basic insulation fails, the live parts may touch the metal casing and there is a risk of electric shock when used. In the previous example, a portable luminaire that was replaced with a Class I metal housing may not be dangerous to the user. China's electronic standard GB8898-2001 "Audio, video and similar electronic equipment safety requirements" has long stipulated that the existence of Class 0 electronic products is not allowed; China's household appliances standard GB4706.1-1998 "Safety of household and similar electrical appliances Part 1: General requirements 》Allow the existence of Class 0 home appliances; China's current effective lamp standard GB7000.1-2002 also allows Class 0 lamps to exist. Compared with Class I luminaires and Class II luminaires, the cost of Class 0 luminaires is lower because of the cost of measures such as grounding or additional insulation. In addition, consumers may not have professional knowledge and often purchase prices. The low luminaires make the Class 0 luminaires occupy a large number of indoor luminaires, especially in the use of household luminaires. This also makes many manufacturers are willing to produce Class 0 luminaires, but has now revised GB7000. 1-2002 standard. The GB7000.1 standard that will be published soon will not allow the existence of Class 0 lamps. In other words, Class 0 lamps are bound to be eliminated in China.
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Dual Band Router Module
Dual-band WiFi module refers to the WiFi module that supports both 2.4GHZ and 5GHz bands. The dual-band WiFi module can operate in the 5Ghz band, which is much cleaner and can easily avoid interfering with each other. The advantage of 2.4G is that it has good ability to penetrate the wall, and the disadvantage is that it is easy to be disturbed. The advantages of 5G are strong anti-interference ability, wide band width, high throughput rate, and strong scalability, but the disadvantage is that 5G is only suitable for indoor small-range coverage and outdoor bridge, and the attenuation effect of various obstacles on it is much larger than 2.4g.
Dual-band WiFi module has a stronger and more stable Wifi wireless signal, higher transmission speed, and can make wireless devices more power-saving, to meet the future high-definition and big data wireless transmission needs.
When selecting a dual-frequency WiFi module, we should pay attention to these parameters of the WiFi module: size, package, frequency range, data rate, transmission rate, transmission distance, communication interface, power supply voltage, antenna interface, etc.
Dual frequency WiFi module can well meet the functional needs of users, increase the competitiveness of the product, while the WiFi module is easy to use, can shorten the user product development cycle, speed up the product market! Users can make choices according to actual needs!
Choosing a dual-band WiFi module may need to pay attention to the following points:
(1) Consider the transmission power of the dual-frequency WiFi module
The transmitting power of the WIFI module is generally about 18dBm, and the transmitting power of the high-power WIFI module is about 28dBm.
(2) Transmission rate
Consider whether the dual-band WiFi module supports MIMO technology (that is, allows multiple antennas to send and receive multiple spatial streams simultaneously)
(3) Consider the application interface that dual-band WiFi modules can provide, which is also very important.
(4) According to the requirements of the application scenario to choose the dual-band WiFi module, not the higher the configuration, the better, the application is good, excess waste!
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Shenzhen MovingComm Technology Co., Ltd. , https://www.movingcommiot.com