What is the difference between a linear and switching power supply?

Linear and switching power supplies are two different technologies used to convert electrical power from one form to another, typically from AC (alternating current) to DC (direct current) in electronic devices. Here are the key differences between the two:

Efficiency:

Linear Power Supply: Linear power supplies are less efficient than switching power supplies. They regulate the output voltage by dissipating excess power as heat. This results in lower overall efficiency, especially when there is a significant voltage drop between the input and output.

Switching Power Supply: Switching power supplies are more efficient. They regulate the output voltage by rapidly switching the input voltage on and off. This allows them to transfer energy to the output with less power loss, making them more efficient, especially in applications where energy efficiency is crucial.

Size and Weight:

Linear Power Supply: Linear power supplies are typically larger and heavier than switching power supplies. The transformer in a linear power supply needs to handle the full input voltage, contributing to the size and weight of the device.

Switching Power Supply: Switching power supplies are generally smaller and lighter because the transformer can be much smaller due to the high-frequency switching.

Heat Dissipation:

Linear Power Supply: Linear power supplies generate more heat because they dissipate excess power as heat. This can require additional heat sinks or cooling mechanisms.

Switching Power Supply: Switching power supplies generate less heat due to their higher efficiency. This is an advantage in applications where heat dissipation is a concern.

Cost:

Linear Power Supply: Linear power supplies are often simpler in design but can be more expensive, especially for higher power applications.

Switching Power Supply: Switching power supplies may have a more complex design, but they are often more cost-effective, especially for higher power applications, because of their higher efficiency and smaller size.

Noise:

Linear Power Supply: Linear power supplies generally produce less electrical noise, making them suitable for applications where noise is a concern.

Switching Power Supply: Switching power supplies can introduce more electrical noise due to the rapid switching of voltages. However, advancements in design have reduced this issue in many cases.

In summary, the choice between linear and switching power supplies depends on the specific requirements of the application, including factors such as efficiency, size, weight, cost, and noise considerations.