Batteries in parallel with a diode

[quantumlight]

I was wondering what the effects are if any if I connect a 17V DC source in parallel with a 9 V battery but the 9 V battery has a diode that prevents current from flowing into it. Thanks

 

[sophiecentaur]

That's OK. Did you want the 9V battery there to give a supply if the 17V fails?
You may also want a diode in series with the 17V supply to prevent the battery discharging back into it when it fails (in case there is a path to Earth inside the 17V supply).

 

[Shikhar]

I was wondering what the effects are if any if I connect a 17V DC source in parallel with a 9 V battery but the 9 V battery has a diode that prevents current from flowing into it. Thanks

no current will flow through the circuit as the voltage drop across the reverse biased diode and the 9V battery will be equal to 17V DC source