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Realizing Reliable and Stable Power Supply: Introduction and Application of Johsun Autotransformer/Step Up & Down Transformer

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The function of an Autotransformer


Step Up & Step Down:

The main function of an Autotransformer is to increase or decrease voltage, by changing the input voltage to the desired output voltage, so it is also called a Step Up & Down Transformer. This type of transformer utilizes the characteristic of sharing a set of coils for both output and input, and achieves the function of boosting or reducing voltage by setting different numbers of taps. When it is necessary to increase the input voltage, the voltage at the input end will be higher than the voltage at the output end; On the contrary, it is necessary to reduce the input voltage to meet the voltage requirements of the output terminal.


Working principle of Step Up & Down Transformer


Electromagnetic induction principle:

The working principle of an autotransformer is based on the principle of electromagnetic induction, which achieves voltage transformation by sharing a part of the coil. Specifically:


Basic structure: The autotransformer consists of a shared coil and one or more independent coils, with one used as the input coil and the other or several used as the output coils.


Working mode: When AC current flows through the input coil, an alternating magnetic field is generated in the coil. This magnetic field is then transmitted to the output coil through magnetic coupling, where an induced electromotive force is generated.


Transformation ratio: The transformation ratio of an autotransformer can be determined by the ratio of the number of turns of the coil, that is, the number of turns of the output coil divided by the number of turns of the input coil. For example, if the number of turns of the output coil is twice that of the input coil, the transformer ratio is 2:1.


Voltage conversion: Autotransformers can achieve an increase or decrease in voltage. When the number of turns of the input coil is greater than the number of turns of the output coil, the output voltage will decrease; On the contrary, if the number of turns of the input coil is less than the number of turns of the output coil, the output voltage will increase.


Features and applications: Autotransformers have a small volume, low cost, and can provide a certain degree of current amplification function. It is widely used in power systems and electronic devices, such as voltage regulation and conversion.


The advantages and disadvantages of a Step Up & Down Transformer


Compared to ordinary transformers, Step Up & Down Transformers are transformers that share the same winding for the first stage. What are the advantages and disadvantages of this type of transformer?




1. Less materials used, low cost


Because the first stage of an autotransformer shares a set of coils, the material cost is naturally greatly reduced compared to isolation transformers of the same capacity.


2. Easy to install and transport


Because it is smaller in size and lighter in weight than isolation transformers of the same capacity.


3. Higher efficiency


Due to design optimization, the efficiency of lifting transformers is usually higher than that of ordinary transformers.


4. Improved the maximum manufacturing capacity of transformers


The maximum manufacturing capacity of transformers is also limited by transportation conditions. Under the same transportation conditions, the capacity of autotransformers can be larger than that of double winding transformers.




Unable to achieve safe isolation effect


Because there is not only a magnetic connection but also an electrical connection between the initial stages of an autotransformer, it cannot play a safe isolation role like an isolation transformer. Therefore, when using an autotransformer, it is necessary to be careful not to accidentally touch it.


4 types of Household Step Up & Down Transformers produced by Johsun Tec:


(If you want to learn about product details, please click on the corresponding hyperlink to enter the product details)


DT/ST series Transformer


STU series Transformer



ZX series Transformer




THG Series Transformer



TC Series Transformer



Johsun Tec Electrical Co., Ltd. has been focusing on the production of power equipment such as voltage regulators, transformers, regulators, inverters, etc. for 20 years, with production and customization capabilities. Through diversified customization services such as OEM/ODM, it meets the market and brand positioning needs of wholesalers, importers, traders, etc., achieving maximum cooperation between the factory and customers. Zhongxiang Technology adheres to the service concept of "serving customers and meeting the market", with the vision of becoming a well-known power brand, committed to continuously providing customers with the highest quality service and creating the most satisfactory products.