What is the power adapter? Power adapter, also known as external power supply, is a power supply voltage conversion device for small portable electronic equipment and electronic appliances. Its function is to convert the high voltage of 220 volts at home into a stable low voltage of about 5 to 20 volts that these electronic products can work, so that they can work normally.It is also a power supply conversion device for small portable electronic equipment and electronic appliances. It is generally composed of a shell, a power transformer and a rectifier circuit. According to its output type, it can be divided into AC output type and DC output type. According to its connection mode, it can be divided into wall type and desktop type. Let's take a look at the detailed classification and advantages and disadvantages of power adapters.
1. Types of power adapters
Power adapters are mainly divided into two types, linear power supply and switching power supply.
1. The linear power supply is to transform the AC through the transformer, and the rectifier circuit rectifies and filters the AC to obtain the unstable DC voltage. In order to achieve the high-precision DC voltage, the power adapter must adjust the output voltage through the voltage feedback circuit. Advantages: This power supply technology is mature, the circuit is simple, and there is no switching power supply with interference and noise. Disadvantages: the voltage feedback circuit works in a linear state, the power consumption of the regulating tube is large, the conversion efficiency is low, and the weight of the equipment is large due to the use of an inductive transformer.
2. 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: the interference to the power circuit is large, and it is difficult to repair in case of failure.
2. 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 DC through a transformer and a rectifier. There is consumption here, and these consumptions will be converted into heat, so it is normal for the power adapter to generate heat. The transformer is made of silicon steel sheets. When the transformer is electrified, it produces magnetic flux, which will cause the force between the silicon steel sheets, thus producing a buzzing sound, which is normal. But too loud is not normal, for many reasons:
1. AC voltage is unstable.
2. The chip is damaged.
3. Inter-turn short circuit.
4. Component is damaged.
3. Application of power adapter
It is widely used in consumer electronics products, providing output power mostly within 100 watts, and the market demand is growing rapidly. Such as battery chargers for electric bicycles, small LCD TVs, laptops, printers, DVD players and set-top boxes.Most of the early power adapters use linear transformers. With the requirements of consumer electronics products for high efficiency and wide input voltage range of power adapters, as well as the increase of copper, iron and labor costs, the original linear transformers in these power adapters are gradually replaced by switching power supplies.
According to the advantages and disadvantages of the two, it is not difficult to distinguish. It mainly depends on the volume, weight and output voltage range. Transformer type, through coil voltage reduction, post-stage rectification, voltage stabilization, large volume, stable performance, high cost of transformer, easy to heat. The switch type is small in size and low in cost, but the components are easily damaged if the quality is not good. The distinction mainly depends on volume and weight, and the difference is obvious.
The power adapter generally refers to the power supply that converts our mains supply into the DC or low-voltage AC required by the notebook, mobile phone, monitor, router, switch and other electrical appliances. For the notebook and mobile phone, the power adapter is the charger, but for most of the others, the power adapter is only a power supply. Before introducing the difference between a charger and a power adapter, let's first understand what a charger is and what a power adapter is. Power adapter manufacturers will give you a good analysis:
Charger: Charger usually refers to a device that converts alternating current into low-voltage direct current. It includes control circuits that meet the charging characteristics such as current limiting and voltage limiting. Chargers are widely used in various fields, especially in the field of life, they are widely used in mobile phones, cameras and other common electrical appliances. It generally charges the battery directly without any intermediary equipment and devices. The process of the charger is: constant current-constant voltage-trickle, three-stage intelligent charging.The three-stage charging theory in the charging process can greatly improve the charging efficiency of the battery, shorten the charging time and effectively prolong the battery life. The three-stage charging adopts first constant current charging, then constant voltage charging, and finally floating charging for maintenance charging.
Power adapter:Most power adapters can automatically detect 100-240V AC (50/60Hz). The power adapter is a power supply conversion device for small portable electronic equipment and electronic appliances. It connects the external power supply with the host by a line, which can reduce the size and weight of the host. Only a very small number of equipment and appliances build the power supply into the host.It is composed of a power transformer and a rectifier circuit. According to its output type, it can be divided into AC output type and DC output type. According to its connection mode, it can be divided into wall type and desktop type. There is a nameplate on the power adapter, which indicates the power, input and output voltage, current and other indicators. Pay special attention to the range of input voltage.
-- LUO --
：2022-12-23