low cost
Power supplies don't fail. Idiot.
A Consort EV265 power supply will begin reading low current and power during component failure like capacitors and resistors. When the appropriate amount of power is not flowing, readings and power output will fluctuate.
The UPS uses batteries to supply power when you have a power failure. There are two main types 1) Switched where the voltage is not applied until the power company voltage is removes and 2) continuous where batteries are continually being charged and running an inverter to supply AC. A generator takes several seconds to come to speed after a power failure is detected. Hence a generator is fine for things like lighting and house hold appliances, but not for computers if you value your data. In an optimum system a UPS may be backed up by a generator since the batteries in an UPS typically are not designed to provide backup power for a long period.
DC Power is Direct Current Power Supply.
ferro-resonant power supply?