battery backup

Overview - I would like to install an Apple AirTag in a vehicle and have it gets its primary power from the vehicle's 12V battery. In the event that the 12V Battery is disconnected, I would like for a backup 3V Battery to continue to provide the power required to run the AirTag. Approach -...

As the title says, i want to build a custom mini pc. The reason i'm not buying just a laptop or a mini pc are many...First of all i want something that will be able to be upgraded in the future without problems, that's why i'm putting a Micro-Atx inside instead of a laptop mobo. 2nd i want...

Hi everyone, I have a primary device that consumes 6.2W on average (5.0V-1.24A). the Input voltage is supplied from a 12Vin through a Buck Regulator. I need to design a power backup circuit that can ensure if my Vin (12V) is unexpectedly lost, The V_backup will immediately supply to my device...

Having repaired an old Kambrook KD36 timer gifted to me by a friend, I'm sharing my circuit schematic and notes for anyone who might find them useful. The timer had been rendered unserviceable due to acid leakage from the two back-up batteries. The leaking acid had damaged some areas of the PCB...