- on Power Supplies
- Published in issue 7/2011 on page 49
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.