Two parallel voltage sources? What happens?

Thread Starter

John5788

Joined Apr 2, 2009
54
I am curious what happens in a circuit like this:



PSpice wont let me simulate it, gives me an error.

What would happen if I built a small circuit like this? Does the 12V just end up charging the 5V battery?
 

bertus

Joined Apr 5, 2008
22,270
Hello,

There will be a large current from the 12 Volts battery to the 5 Volts battery,
that is only limited by the internal resistance of the batteries.

Greetings,
Bertus
 

viip

Joined Apr 16, 2009
23
practically due to internal resistances current will flow in to 5v battery....but still i think am gonna try it....lets see how will it smell during blowing job [:D]
 

millwood

Joined Dec 31, 1969
0
I would put a resistor in serial with one of the batteries, like 10ohm 10w, or something like that.

batteries have very low internal resistance (from a few mohm to 30-50mohm, depending on the type). a 5v voltage drop over this kind of resistance will cause massive amount of current.

I see sparks, :).
 

hobbyist

Joined Aug 10, 2008
892
1.) Who knows, since it's 2 electrodes seperated by a electrolyte, maybe initially it would act like a capacitor??? Before overheating......

2) .But then again when you do dc analysis (superposition) on it you replace it with a short.
So it would be a low value resistor in parrallel with the 1 K.

I say, # 2. is my final answer...
 
Last edited:

Von

Joined Oct 29, 2008
65
Batteries are not equivalent to electrical "shorts".

Why do you expect it to ACT like (or simulate) one?

Do it outside!
 

millwood

Joined Dec 31, 1969
0
Batteries are not equivalent to electrical "shorts".
they are, at least during a short burst.

if you were to parallel two batteries, the current going from the high voltaged one to the low voltaged one will just be the voltage differential / total internal resistance of the two amps.

in this case, the total internal resistance is likely in the .1ohm range, and the voltage differential is 5v. so you are talking about a 50amp current flow.

spark!
 
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