Hi there people

I am making a Home Alarm System using a PIC16F877 Microcontroller and the thing is I want to have a back up battery, but i don't know the circuit for it, my system is working on 5V so the back up battery should be at 5V as well, i want to have a backup battery so that if someone cuts my Main supply the system should go to backup battery

so if someone can tell me the circuit for a backup battery can you please let me know.

Thanks for your time and help

With Regards

Maxster

 

Its not necessary to have a back-up battery of 5V. You could go for a battery of higher voltage ratings eg. 6V, 9V, 12V...etc. which are easily available & cheaper. You can develop a voltage divider ckt. (with a little help from electronics DIYs) or go for a voltage regulator IC with input rating of say 6V, 9V or 12V and output as 5V available commercially .

Voltage regulator ICs with input rating as high as 35V and output of 5V is also commercially available. I hope this helps.