The most common way of dealing with such circumstances is to use uninterruptible power supplies (UPS) to cover these brief downtimes, thus ensuring high reliability continuous operation of the system. Similarly, many of today’s emergency and standby systems are used to provide backup power for building systems to provide assurance that safety systems and critical equipment can maintain their operation during a power outage – whatever its cause.
Another obvious example can be readily found in the ubiquitous handheld electronic devices which are used in our everyday lives. Because dependability is paramount, handhelds are carefully engineered with lightweight power sources for reliable use under normal conditions. But, no amount of careful engineering can prevent the mistreatment they will undergo at the hands of humans. For example, what happens when a factory worker drops a bar code scanner, causing its battery to drop out? Such events are electronically unpredictable and important data stored in volatile memory would be lost without some form of safety net – namely a short-term power holdup system that stores sufficient energy to supply standby power until the battery can be replaced or the data can be stored in permanent memory.
These examples clearly demonstrate the need for an alternative form of power source to be available, just in case there is an interruption of the primary power source.