Standby UPS Systems have three main components: 1) a surge/noise filter, 2) a battery and 3) an inverter/charger. During operation under normal voltage conditions, the UPS passes input voltage through the surge/noise filter before delivering it to the connected equipment. It also uses its inverter/charger to charge the battery, preparing it for use during a blackout or brownout. During operation under blackout conditions, the UPS converts DC power from the battery into AC power to support connected equipment.