corsair power supply tx850 side view How power supplies work

Even though power supply units are the most critical part of almost every electronic device, being a component absolutely vital to their operation, they rarely are given the attention they deserve. Almost no technology equipment can operate without them since electronic devices cannot operate using the utility grid AC voltage, which also varies in level and frequency depending on your position on the planet.

There are more than eight types of power supplies currently available; in this article we are going to focus on only the two types available for household and business equipment: linear and switching power supplies.

Even though power supply units are the most critical part of almost every electronic device, being a component absolutely vital to their operation, they rarely are given the attention they deserve. Almost no technology equipment can operate without them since electronic devices cannot operate using the utility grid AC voltage, which also varies in level and frequency depending on your position on the planet.

There are more than eight types of power supplies currently available; in this article we are going to focus on only the two types available for household and business equipment: linear and switching power supplies.

Several people may believe the power supplies are limited to computer applications. That is incorrect since almost every piece of technology need a power supply to operate. Some examples include and are not limited to your phone charger, your TV and your alarm clock. As we mentioned before, no electronic equipment can operate on AC voltage. It is the power supply's job to convert AC voltage to another form, suitable for the equipment. Or, to be even more accurate, the definition of a power supply is that "it is an apparatus designed to convert one form of electric energy to another".

The vast majority of users are simply not aware of the presence of power supplies because they are integrated into the equipment. Most of them are not replaceable because those devices have no expandability or upgradeability and are (hopefully!) designed to exceed the product's lifetime. For example, you cannot replace the power supply of your TV because there is no way to upgrade or expand your TV and force it to require more power, meaning that ultimately there is no reason to perform a power supply upgrade. Computers are an entirely different matter; they are fully expandable and customizable, meaning that not only each and every one of them has different power needs but that the needs of every single computer can be altered several times during its operational lifetime.

A power supply transforming the utility grid AC voltage to DC voltage for the equipment to use must perform certain functions at the highest possible efficiency and at the lowest possible cost. The basic functions usually are:

  1. Rectification – Convert the input AC voltage to DC voltage.
  2. Voltage transformation – Adjust the supplied voltage to the required levels.
  3. Filtering – Smoothen the ripple of the supplied voltage.
  4. Regulation – Control the supplied voltage regardless of line, load and / or temperatures changes.
  5. Isolation – Electrically isolate the input voltage source from the output.
  6. Protection – Prevent any damaging power phenomena from reaching or take effect at the output.