Linear DC power supplies have a transformer that reduces AC input to a lower voltage and also acts as a safety barrier for the low voltage output from the AC input. The AC output is then converted to low-voltage DC output, which is regulated into the required output voltage. Switch mode DC power supplies, in comparison, use diodes and capacitors to rectify and smooth AC voltage.
This voltage turns into a high voltage DC, which is converted into a safe, low voltage with high frequency. Another common type of DC power supplies, the DC/DC converter, works by converting a source of direct current from one voltage to another.
Many applications utilize DC power supplies. Two very common uses are in cellular phones and laptop computers. They can also be used in telecommunications equipment, medical equipment, video technology, computer flash memory, and process control systems. All types of DC power supplies have the ability to be PCB mount, wall mount adapters, rack mount, internal or open frame, desktop, or DIN rail.
DC power supplies can accept input voltages such as DC input, AC single phase, or AC three phase, with common outputs of DC power supplies being 3.3V, 5V, 12V, 15V, 24V and 48V. DC power supplies can come with many types of user interfaces and can use different operating temperatures as well.