source switching AC and battery

[Harryz]

Good day.
I have a project which involves source switching (I don't know what to call). What I want to happen are:
I have a AC supply and a battery supply. When not plugged in, of course, the battery is the supply and when plugged in, the AC is the supply and at the same time charging the battery. How can I do this? Please help me. I really need this. I am not very fond on electronics. Thanks for the help.
I don't know if this is the right section for my problem. Thanks anyway.

 

[SherpaDoug]

Generally one uses a "diode OR" function. Connect a diode from each source to the load. Whichever source is supplying a higher voltage turns on its diode and supplies the circuit. Any sources that are not active generally supply zero voltage. In your case set the AC supply to provide a little higher voltage than the battery, but both within the voltage spec of the load.

 

[Harryz]

Generally one uses a "diode OR" function. Connect a diode from each source to the load. Whichever source is supplying a higher voltage turns on its diode and supplies the circuit. Any sources that are not active generally supply zero voltage. In your case set the AC supply to provide a little higher voltage than the battery, but both within the voltage spec of the load.

Thanks for this. I kinda understand but not enough. Can you show me a sample diagram? Thanks Mr. Sherpa

 

[SherpaDoug]

The two diodes on the right pass whichever voltage is higher to the VCC line

 

[Harryz]

View attachment 111502

The two diodes on the right pass whichever voltage is higher to the VCC line

Thanks for this. I'll study it carefully.