neazoi
Advanced Member level 5

I have found this circuit which comes from elektor
DIY Electronics Projects and Electronic Circuits Diagrams: 9V DC Adapter With Battery Backup
I was wondering what is the purpose of R2 ??
Also can I use 1.2v ni-cd batteries in series, will they be charged and discharged ok, instead of a big 12v one?
Also I see no reason why I could not substitute the IC with a 7805 to get 5v instead of a 7809, is this ok?
DIY Electronics Projects and Electronic Circuits Diagrams: 9V DC Adapter With Battery Backup
I was wondering what is the purpose of R2 ??
Also can I use 1.2v ni-cd batteries in series, will they be charged and discharged ok, instead of a big 12v one?
Also I see no reason why I could not substitute the IC with a 7805 to get 5v instead of a 7809, is this ok?