Power Supply Wiring HELP!!!!!!

[nathanbrown03]

1st of all I want to introduce my self. Im nathan and i do alot of simple electronic projects and soldering.

Anyway here my delima.

I told my boss i knew how to fix his small electric gun safe so that he would not have to put 2 new 9v batteries in it every 3 months.

Anyways i have the 9 volt power supply but i do not know what circuitry to add so that current does not fry the batteries if i kept them in the safe. the only idea i had was to ad diodes to the battery to keep the voltage from getting to the batteries... but would that keep the batteries from draining???

It would be nice for the safe to work if the power went out. If it is to hard i will just power the safe from the transformer alone.

Thank you for any help you may have
im gunna try to complete the project tonight either way.

Thanks
Nathan

 

[IanP]

All what you need to do is to configure your supply system in OR configuration .. see attched picture ..
And, don't worry, for as long as the mains voltage is present the battery is safe and no current is drawn from it (of course the dc voltage from the mains section has to higher than that from the battery) ..

Regards,
IanP