Introduction to the types and functions of power adapters

　　In some small portable electronic devices, such as phone and parent machine, game console, language repeater, walkman, notebook computer, cell phone, etc., we often find power adapters. So what is a power adapter? And what is its function? This article will explain to you one by one.

　　What is the power adapter? The power adapter is also called an external power supply. It is a power supply voltage conversion device for small portable electronic devices and electronic appliances. Its function is to convert the high voltage of 220 volts at home into 5 volts to 20 that these electronic products can work. The stable low voltage around volts allows them to work normally.

　　1. Type of power adapter

　　There are two main types of power adapters, switching power supplies and linear power supplies.

　　1) Switching power supply is a kind of power supply that uses modern electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. The switching power supply of power adapter is generally composed of pulse width modulation (PWM) control IC and MOSFET

　　Advantages: High working efficiency, small size, and can work in a wide voltage range.

　　Disadvantages: Great interference to the power circuit, difficult to repair when a fault occurs.

　　2) The linear power supply transforms the AC power through a transformer, and the rectifier circuit rectifies and filters to obtain an unsteady DC voltage. To achieve a high-precision DC voltage for the power adapter, the output voltage must be adjusted through a voltage feedback circuit.

　　Advantages: This kind of power supply technology is mature, the circuit is simple, and there is no interference and noise of the switching power supply.

　　Disadvantages: The voltage feedback circuit works in a linear state, the power consumption of the regulator tube is large, the conversion efficiency is low, and the weight of the equipment is heavy due to the use of inductive transformers.

　　2, the nameplate of the power adapter

　　There is a nameplate on the power adapter, which indicates the power, input and output voltage and current and other indicators. As shown in the figure, there are generally several items on the label of the power adapter (hereinafter referred to as adapter) that need to be paid attention to. The first is the model of the adapter. For example, the model of this adapter is XVE-120100. It tells us a few information about its manufacturer, main parameters, etc. The beginning of XVE is generally ##Company code, 120100 is the description of this The adapter is 12W, 050200 is 10W; the second is the INPUT of the adapter, which is generally 100-240V~50-60Hz in China, which shows that this adapter can work normally under the voltage of 100V-240V ; The third is the adapter's OUTPUT (output). Two numbers can quickly calculate the wattage of the adapter. For example, for this adapter, voltage 12V * current 1A12W (power), indicating that this power supply is a 12W adapter.

　　3. The role of the power adapter

　　The role of the power adapter is a transformer and a rectifier. Home AC power is 220v, and our computer uses DC 12v (as if it is), so we can be sure that the power adapter is a transformer and rectifier. Then the adapter is a transformer. We should all know that AC 220v is transformed into a voltage through a transformer and transformed into a direct current through a rectifier. There is consumption here, and these consumption will be converted into heat, so it is normal for the power adapter to generate heat. The transformer is made of silicon steel sheets. After the transformer is energized, magnetic flux will be generated. The magnetic flux will cause force action between the silicon steel sheets, resulting in a buzzing sound. This is normal. However, the sound of the overfire ground is abnormal. There are many reasons: 1. The AC voltage is unstable. 2. The chip is damaged. 3. Short circuit between turns. 4. The component is damaged.

　　4. Application of power adapter

　　is widely used in consumer electronic products, most of the output power provided is within 100 watts, and the market demand is growing rapidly. Such as electric bicycle battery chargers, small-size LCD TVs, notebook computers, printers, DVD players and set-top boxes, etc. have applications. Most of the early power adapters used linear transformers. As consumer electronics products require high efficiency and wide input voltage range for power adapters, as well as the increase in copper, iron, and labor costs, most of the original linear transformers in this type of power adapter gradually Replaced by switching power supply.

　　Summary: This article mainly helps you to understand the concept of what a power adapter is. It focuses on introducing the types, functions and applications of power adapters. However, with the continuous development and progress of science and technology, the application practice of various scientific research projects affects the power adapter. The demand for power supply has increased year by year, and many new requirements have been put forward for its accuracy, performance, specifications, variety, type, volume, etc. The existing power adapters can no longer meet the current needs, research and development of suitable new power adapters Has become an objective demand, and its social and economic benefits are relatively significant, and the market prospects are relatively bright.

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