What is PSU and PDU?


Power Supply Unit

What is a PSU and what does it do? PSU stands for power supply unit, an internal IT hardware component. Instead of supplying the systems with power, it converts the electricity source into the correct voltage. By receiving power from an electrical outlet, it converts the current from AC (alternating current) to DC (direct current).

Why is a PSU important?

The power supply unit is a crucial component for any server. Without it, your IT infrastructure can’t function. When choosing a PSU, it is important to check its compatibility with the form factor of your server and motherboard. To determine how much power it can provide to computers, you must consider the rating of PSUs. The higher wattage rating, the more power the unit can provide.

PSUs have essential functions and operate differently depending on the device. It can modify the voltage, convert power to DC from AC, or regulate power for a smoother voltage. The main components typically consist of the AC supply, transformer, rectifier, filter, regulator, and DC output. Not all power supplies contain these components, but they are essential functions.

  • AC Supply: alternating current
  • Transformer: changes the incoming voltage to the necessary outgoing voltage
  • Rectifier: converts incoming power from AC to DC; is either half-wave, full-wave, or bridge
  • Filter: regulates the flow from AC to DC for a smooth voltage
  • Regulator: reduces the ripple voltages left by the filter and removes any voltage surges or drops, preventing damage to devices plugged into the power supply
  • DC Output: direct current

Power Distribution Unit

PDUs are responsible for distributing reliable network power to your multiple devices. It can deliver AC or DC power from an uninterruptible power supply, a generator, or utility power to equipment. Commonly used in data centers, PDUs distribute electrical power to connected servers. The most basic form of a PDU is a large industrial-grade power strip used to power servers and telecommunications equipment. Power strips are used to supply power to rack mounted equipment such as servers, switches, and routers. The power strips are designed to provide standard electrical outlets and do not require monitoring or remote access capabilities. These power strips can also be powered from either the front or the end of the unit.

15A Horizontal Rackmount Power Strip
15A Horizontal Rackmount Power Strip

Rack PDUs can be mounted directly into industry-standard server racks and distribute the power supply to specific servers, switches, and data center devices. The server racks are either 19”or 23” in width. A rack-mountable PDU is different from other PDUs that are designed to be wall-mounted or attached to the side of the equipment. Basic PDUs that supply power to server racks without advanced functionality are low-cost power distribution options. If you have multiple devices, then power strips will help you plug them all directly into your power supply. This is possible because PDUs can turn one power input into multiple power outputs.

Vertical Rackmount Power Strip
Vertical Rackmount Power Strip

Rackmount Power Strips and PDU:

By using RackSolutions power strips, you can easily plug equipment right into your rack. Our power strips are CSA certified and UL recognized, compatible with any EIA 19” rack, and provide power from either the front or the rear of the unit.


What is PSU and PDU?
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What is PSU and PDU?
PSU is an internal IT hardware component that converts the electricity source into the correct voltage. PDU distributes reliable network power to multiple devices.
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