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Power adapter you don't know the secret

time2006/10/09

The power adapter doesn't look very big, but it contains too much knowledge. Today we will talk to you to enhance your understanding of the power adapter.
The power adapter doesn't look very big, but it contains too much knowledge. In the past, I always explained the common sense knowledge or problems of some power adapters. Those are very common. Let's talk to you today. Talk about some of the unpopular knowledge of adapters, so as to enhance everyone's understanding of the power adapter, then let's take a look at some of the little-known secrets:

1."Power input isolation transformer" is actually an isolation transformer connected to the power input.
The power input isolation transformer, the term seems to be very tall, and often makes it difficult for newcomers who are new to electrical engineering to learn. In fact, the meaning behind this term refers to the connection of an isolation transformer at the output of the power supply. In the final analysis, this definition is mainly to understand the expansion of the isolation transformer. After an isolation transformer is connected to the power input end, the primary and secondary coils of the isolation transformer are isolated, thereby ensuring safe operation of the power supply system. This is also the main role of the power input isolation transformer. Generally speaking, the isolation transformer is mostly suitable for a power transmission range with a small transmission range and a short line. At present, many electrical appliances are directly connected to the 220V mains power grid, and the electrical appliances use low voltage, so it is necessary to step down through the power transformer. If you do not use an isolation transformer, there is a danger of electric shock. Therefore, an isolation transformer can be connected to the power input to ensure the safe operation of the appliance.

2.The testing method of low frequency transformer and high frequency transformer is different.
In the application process of the power transformer, the transformer products are divided according to different working frequencies, and can usually be divided into low frequency transformers and high frequency transformers. Although the working principle of the two is the same, in fact, the testing principle of the low frequency transformer and the high frequency transformer is different. During the test, the low-frequency transformer can directly transform the alternating current. The items it tests are mainly the output voltage and related parameters. Including no-load input current, no-load output voltage, on-board input current, on-load output voltage, efficiency and withstand voltage. The high-frequency transformer needs to work with the circuit to work, so its test items are mainly related to the performance test. The main contents of the test include inductance, leakage inductance, turns ratio and withstand voltage.

3. The common audio power transformers currently on the market are basically toroidal transformers.
Can the audio power transformer and the ordinary power transformer be used interchangeably? The answer is of course: no. At present, the common impression power transformers on the market are mostly ring-type transformers. In practical applications, toroidal transformers are often called "ring cows". This type of transformer is easy to install, has high conversion efficiency, and has the characteristics of small magnetic leakage. In terms of weight, the toroidal transformer can be half the weight of the laminated transformer, and the cost is lower than that of the ordinary square transformer. In the manufacturing process, the winding evenly surrounds the toroidal core, effectively reducing the magnetostriction. Noise is also good for heat dissipation. The reason why the switching power supply transformer can not be applied to the audio power supply is because the high frequency interference of the switching power supply is too serious, which will greatly affect the sound quality of the sound.