Power adapter is a power supply device for external power supply of electronic equipment. Due to the limited internal space of small portable electronic equipment and electronic appliances, the power supply conversion equipment is separated. Its function is to convert the mains 220V AC high voltage. It is converted into a low-voltage DC around 3.3V to 24V for electronic equipment, so that the electronic equipment can work normally, and it is widely used in small electronic products such as smartphones, tablets, liquid crystal displays, routers, game consoles, and notebook computers.
The traditional linear power adapter is composed of a transformer and a rectifier filter circuit (some include a linear regulator), which is not only large in size, poor in voltage stabilization, but also low in power conversion efficiency. New switching power supply adapters by Alrightpower, a professional power adapter manufacturer, generally use miniaturized fully sealed switching power supply modules without power frequency transformers, which have the advantages of high efficiency, small size, good voltage regulation, and complete protection functions, and can completely replace traditional linear power adapters.
Basically all laptops and tablets have an external power supply, and use a cable to connect to the laptop and tablet host, which can reduce the size and weight of the host. Only a few models have the power supply built in the host. There is a nameplate label on the power adapter (currently some products are laser engraving nameplates), which indicates the power supply type, input and output voltage and current indicators. We should pay special attention to the input voltage range. If the input is only a single 100V, the input voltage will be burnt when plugged in under 220V mains voltage.
1. The voltage of the general power adapter refers to the rated output voltage, and the progress is usually ±5%, that is to say, when the rated output 12v 10a power adapter, the output voltage range is between 11.4V and 12.6V. The output plug of the power adapter is not connected to any electronic equipment, and there is no voltage when the device is loaded, so it can also be understood that this voltage is the highest value of the output voltage of the power adapter.
2. The power adapter uses a sampling feedback loop with active voltage stabilization. Even if the input AC voltage (mains power) fluctuates, its output is a constant value; the general small transformers (linear transformers) on the market do not have active voltage stabilization. If the mains power fluctuates, the output of the power supply will fluctuate accordingly.
3. Generally speaking, the no-load voltage of the power adapter may not be exactly the same as the nominal voltage. Considering that there will be some loss when the DC wire passes current, the no-load voltage of the power adapter is usually set higher than the nominal voltage, such as 1.02-1.05 times higher.
4. Regarding the nominal current value, it indicates the load capacity of the power adapter. Regardless of the internal rectifier diode and output DC wire of any power adapter, whether it's electrical adapter for Japan or for other areas, there is a certain internal resistance. Therefore, when the power adapter outputs current, there will be losses in the rectifier diode and the DC line, resulting in two things, one is to generate heat, so the power adapter will be hot, and the other is to cause the output voltage to decrease. The no-load voltage of the power adapter is a little different from the voltage with a load. The deviation is normal within the range of ±5%.
The power adapter is constant voltage, not constant current, and the difference from the charger: the charger has constant current characteristics and can directly charge the battery; while the adapter is a constant voltage type, it can only charge the battery with the help of a charge management circuit. Charge the battery directly. The power adapter is mainly used for powering electronic devices. The output characteristics of the two are different. The power adapter is guaranteed to output the rated voltage within the rated load range; the charger (simple type) is CC/CV, that is, it is in constant current mode before being fully charged, and the output current is 0 when fully charged.