Etone Power Co., Ltd.
In this type of UPSs the load is directly connected to the incoming AC power supply. When this mains supply fails or goes below a minimum level, the offline UPS blocks the incoming AC mains and deliver power to the load via internally connected battery using DC-AC inverter circuitry. Although all manufacturer tries to minimise the switching delay but it could be as long as 25 milliseconds. Generally for home desktops we use offline UPS.