This is a simple Electronic Router UPS Circuit Diagram Project. It can be handy to have your phone and Internet router continue working for a while after a power failure for example, if they provide access to a security system. This requires a backup power supply for the router. The version described here consists of a 12-V lead-acid battery and a voltage converter capable of supplying an output voltage in the range of 15 to 30 V. It has built-in protection to prevent excessive battery discharge. This is uninterruptible power supply (UPS) operates in standby mode as long as the mains voltage is present. Router UPS Circuit Diagram The UPS consists of four parts: a backup detector circuit that monitors the supply voltage from the AC mains adapter, a battery circuit that monitors the battery voltage to prevent it from dropping below 11.8 V, a FET switch between the battery and the voltage conve...