Simple battery backup circuit

Thread Starter

Michel_e_r

Joined May 30, 2008
10
I'd like to design a simple circuit which is usually connected through an adapter and when it is not, it uses a common 12V battery or of the sort. How can I do this? I've thought of using relay and somehow make that work, but seems it will take more than that =P. Any ideas? Much thanks.
 

SgtWookie

Joined Jul 17, 2007
22,210
Your request is really quite vague.

What is your required voltage and current for sustaining the circuit?
DC or AC? AC gets quite a bit more complicated.
 

Thread Starter

Michel_e_r

Joined May 30, 2008
10
12 volts and AC circuit =/

So, all I have is a power source adapter which is connected to the wall and when it is unplugged I need a battery to serve as backup to supply the voltage to the the rest of the circuit.
 

SgtWookie

Joined Jul 17, 2007
22,210
12 volts and AC circuit =/
So, 12VAC at what current? :confused:

So, all I have is a power source adapter which is connected to the wall and when it is unplugged I need a battery to serve as backup to supply the voltage to the the rest of the circuit.
OK, so if it's a "wall wart" that's supplying the juice, it may not be AC, it could be DC.

Still do not have much to go on here. :confused:
 

Wendy

Joined Mar 24, 2008
22,145
If you are using DC (say a wall wart and a battery) then simple diodes will do the trick. Just make sure the wall wart has at least a couple of tenths more voltage than the battery, and the switching is automatic.
 

Thread Starter

Michel_e_r

Joined May 30, 2008
10
Thank you SgtWookie and Bill_Marsden for putting up with my vagueness..English is not my strong language ;). I didn't know what a wall wart was but it sure is what I have. I read through other thread of using diodes and I'm sure that is what I need but I just started with electronic and not sure as to how to put it all. Is there a circuit available I can use as reference perhaps?


Much thanks

P.S This whole thing is to connect lights..so around 100mA-200mA. Very similar to this persons project..except he had schematic for which i do not have and is what I need.

http://forum.allaboutcircuits.com/showthread.php?t=3106
 
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