The working principle and classification of linear power supplies
A linear power supply is an electronic device that converts alternating current into stable direct current. The basic working principle is to use a transformer to reduce the voltage of AC power and rectify it into DC power, and then stabilize the DC power at the required voltage level through a voltage regulator circuit.
Specifically, the working principle of a linear power supply includes the following steps:
Transformer voltage reduction: The input AC power is reduced through a transformer, usually using a large inductance coil and a magnetic core to reduce the input voltage to the required level.
Rectification: Converting stepped down AC power into DC power, typically using rectification circuits such as single-phase or three-phase rectifier bridges to convert AC signals into unidirectional DC signals.
Filtering: Using capacitors and other components to filter direct current, removing pulsating components from the direct current to obtain a more stable direct current signal.
Voltage stabilization: Using voltage stabilization devices such as diodes, transistors, integrated circuits, etc., to stabilize DC power and ensure the stability of output voltage.
Output: Provide stable DC power to the equipment that needs to be used.
It should be noted that the output voltage of a linear power supply is usually related to the input voltage, such as the output voltage being equal to the input voltage minus a certain voltage drop, so it needs to be adjusted and designed according to specific requirements.
Linear power supplies can be classified in different ways, and the following are common ways to classify linear power supplies:
According to the type of input power supply, it can be divided into AC input type and DC input type. AC input type usually requires an external transformer to convert AC power into the required DC voltage. The DC input type can directly accept DC power input.
According to the characteristics of output voltage and current, it can be divided into constant voltage type and constant current type. The output voltage of a constant voltage linear power supply is stable, and the output current can vary according to changes in the load. The output current of a constant current linear power supply is stable, and the output voltage varies with the load.
According to the voltage regulation method, it can be divided into ordinary voltage regulation type and open-loop voltage regulation type. The ordinary voltage stabilizing type uses feedback circuits to control the output voltage stability, requiring the use of voltage stabilizing devices such as transistors, diodes, integrated circuits, etc. The open-loop voltage regulator type does not have a feedback circuit and usually uses potentiometers and other means to adjust the output voltage. The output voltage stability is poor, but the cost is lower.
According to power level, it can be divided into low-power type and high-power type. Low power models generally have lower output power and are suitable for powering small electronic devices such as power banks and audio equipment. High power type is suitable for supplying power to large electronic devices, such as industrial equipment, robots, machine tools, etc.
According to the application field, it can be divided into universal and specialized types. The universal type is suitable for various electronic devices, such as computers, mobile phones, digital cameras, etc. The specialized type is suitable for specific fields, such as medical equipment, military equipment, etc.
