Simply put, the inverter is a kind of low-voltage (12 or 24 volts or 48 volts) direct current into 220 volts AC electronic devices. Because we usually 220 volts AC into DC rectifier to use, and the role of the 500w charge inverter on the contrary, hence the name. We are in a "mobile" era, mobile office, mobile communications, mobile leisure and entertainment. In a moving state, the people not only need low-voltage direct current from the battery or battery supply, but also an essential need in our everyday environment 220 volts AC inverter to meet us this demand. Inverter free two main categories, one is sine wave inverter, and the other is a square wave inverter. Sine wave inverter output is the same as the grid we use every day even better sine wave AC, because it does not exist power of electromagnetic pollution. Square wave inverter output is the poor quality of the square wave AC, its positive maximum to negative almost at the same time generate the maximum, so causing severe destabilizing effects on the load and the inverter itself. Meanwhile, the load is low, only 40-60% of the rated load, not with inductive load (explained in detail below article). As the load carried is too large, square-wave current third harmonic components contained will flow into the capacitive load current increases, severe damage to the load of the power supply filter capacitor. In response to these shortcomings, in recent years there has been quasi-sine wave (or modified sine wave, modified sine wave, sine-wave, etc.) of the inverter, the output waveform from the positive maximum to the negative maximum value between the time there is a spacing effect has improved, but is still quasi-sine wave is composed of a line, belonging to a square wave areas, poor continuity. In conclusion, sine wave inverter providing high-quality alternating current, can bring any kind of load, but the technical requirements and costs are high. Quasi-sine wave inverter can meet most of our electricity demand, high efficiency, low noise, moderate prices, and thus become the market mainstream. Square wave inverters produced using simple multivibrator, its technology is the level of the 1950s, will gradually withdraw from the market. According to the power inverter hair, divided into coal inverter, solar inverter, wind inverter, nuclear inverter. Depending on the application, divided into independent control of the inverter, and inverter. Inverter efficiency as described above, the inverter work itself should consume some power, therefore, its input power is greater than its output power. Efficiency of the inverter that is inverter output power and input power ratio. If a single inverter 100 watts of DC power input, the output of the 90-watt AC power, then its efficiency is 90%. The world solar inverters, high efficiency in Europe and America, the European standard is 97.2%, but the price is more expensive, the domestic market is only Shenzhen Green New Energy Co., the largest pure sine wave inverter efficiency can reach 95% or more, domestic other inverter efficiency is 90% or less. In addition to efficiency, select the inverter waveform is also very important.