What happens to your alarm clock when you have a power outage? Will you lose all of your clock settings?
Electric alarm clocks that have no battery must be reset every time the power is cut off or if they are moved. Even if power is cut off for a second, most clocks will still have to be reset. This is a particular problem with alarm clocks that have no “battery” Backup, because even a very brief power outage during the night usually results in the clock failing to trigger the alarm in the morning.
To reduce the problem, many devices that are designed to operate on household electricity incorporate a battery backup to maintain the time during power outages and during times of disconnection from the power supply. More recently, some devices incorporate a method for automatically setting the time, by using using a broadcast Radio time signal from an atomic clock getting the time from an existing satellite television or computer connection, or by being set at the factory and then maintaining the time from then on with a quartz movement powered by an internal rechargeable battery.
Many digital alarm clocks with battery backup use 9V batteries for battery backup, but there are some brands that use AA and AAA for their backup batteries.