How to distinguish between linear power supply and switching power supply
1. Working principle: A linear power supply uses a coil transformer to reduce voltage and stabilize output. Its working principle is relatively simple, but its efficiency is relatively low. Switching power supplies, on the other hand, use switching devices such as MOSFETs to convert and adjust voltage at high frequencies, and adjust the output voltage through switching actions, which has high efficiency.
2. Efficiency: The efficiency of switching power supplies is usually high, which can achieve high energy conversion efficiency, usually above 80%. The efficiency of linear power sources is relatively low, generally between 50% and 60%.
3. Size and weight: Linear power supplies are usually bulky and relatively large because they use coil transformers to reduce voltage. Switching power supplies are more compact and relatively small, due to the use of high-frequency switching to achieve voltage conversion.
4. Cost: In general, the manufacturing cost of switching power supplies is relatively low because they use fewer materials and component quantities. The manufacturing cost of linear power sources is relatively high, due to the need to use more coil transformers and larger heat sinks and other components.
5. Stability: Linear power supplies typically have low noise and good stability, providing a cleaner output power supply. Switching power supplies may generate some electromagnetic interference and noise due to high-frequency switching.
It is very important to choose the appropriate power supply type based on specific application scenarios and requirements. Linear power supplies are suitable for applications with high requirements for power quality and low requirements for noise and interference, while switching power supplies are suitable for applications with high requirements for power density, efficiency, and cost.
Why is a linear power supply called linear
Linear power sources are called "linear" because the relationship between their output voltage and input voltage is linear.
In a linear power supply, the input voltage is reduced (or boosted) by a transformer and the output voltage is stabilized through a linear regulator. A linear regulator adjusts the output voltage by adjusting the on and off states of devices such as tubes or transistors to maintain stability.
The working principle of a linear power supply is relatively simple, and the voltage relationship between input and output is linear, meaning that changes in input voltage are directly reflected in the output voltage. When the input voltage changes, the linear power supply linearly adjusts the output voltage through a voltage regulator to maintain a constant output voltage.
Due to the fact that the regulation process of linear power sources is based on linear relationships, they are referred to as "linear" power sources. On the other hand, switching power supplies adjust the output voltage through the switching action of switching devices, and their working principle is not linear.
Although linear power sources have linear input output characteristics, their efficiency is relatively low because voltage regulating devices consume a certain amount of power. This is also one of the reasons why switching power supplies are more common in high-efficiency applications.
