Normal mains power is in the form of an Alternating Current (AC) Sinusoidal (sine) Waveform. The 'Sinewave' is a smooth constantly varying voltage that forms the basis of modern power distribution systems.
What does that have to do with my UPS?
The equipment you connect to your UPS has been designed to operate on AC power in the form of a sinewave.
So a True Sinewave UPS is good?
Yes. A UPS has two main purposes, to provide power to your equipment when the mains power goes off, and to provide 'clean' power to you equipment. A True Sinewave is clean power.
What about a Modified Sinewave?
A Modified Sinewave, or Stepped Sinewave is an approximation of a Sinewave, that is normally deemed to be sufficient for operating equipment on for short periods. Its a case of something is better than nothing. Modified Sinewave UPS are cheaper to engineer and produce, so they fill the bottom end of the market. While suitable for some equipment they are not suitable for all equipment, and equipment should really only be operated on a Modified Sinewave for short periods.
Do I really need a True Sinewave UPS?
For high end servers, Yes. There are several reports of some brands of servers being completely incompatible with the Modified Sinewave so a True Sinewave UPS is the only way to go.
For lower end equipment, you don't need to have it, but it is a good thing to have.
So for my home PC a Modified Sinewave UPS is fine?
It is, but we recommend that you do not operate your equipment on the UPS for long period. Some users report that when their Modified Sinewave UPS is operating on batteries they get a buzzing noise from their power supply, monitor, and speakers.
Hang on, the UPS is on all the time?
If you have a Modified Sinewave UPS, it will be a Standby or Line Interactive type. This means that until the power actually fails the UPS is passing the mains power Sinewave through to your equipment. It is only when the power fails that your UPS begins to operate on batteries and provides the Modified Sinewave, and thats when you should be shutting down your equipment as soon as convenient.
