[LinuxUsers] Sine wave vs shaped square wave

[Gregg Rawson]

There is an additional feature on some online UPS's where there is
buck/boost circuitry. If there is a brown out, and it is just above the
cutoff voltage, the equipment will keep running on the low voltage on a
normal UPS. With the buck/boost feature, the voltage will be brought up
or down to a normal level as required.

Gregg

> Big part of the problem though relies on the inverter switching at the
> moment of power failure, so the most expensive UPS's run on battery
> all the time and the charging circuit is always on. These are the
> online UPS's.