There are 2 sources.

Source (A) 5VDC @ Max 1000mA

Source (B) 20VDC @ Max 50mA

If the grounds of both "source(s)" are "common".

Would Pos source (B) flow to Pos source (A)
or
Would Pos source (A) Flow to Pos Source (B) because source (A) has a higher *current* potential?

 

It's based upon the voltage potential between the two, so the higher voltage always wins.
The current will equal the voltage difference divided by the combined series resistance of the two sources.

But, of course, you normally don't want to connect the two in practice, because it will likely zap something.

The current rating (potential is voltage, not current) has no effect on that unless there is a current-limit circuit in one or both of the sources.

 

The 5V source might or might not be able to sink current. If it is a battery, the current into it would be a charging current. The could cause a fire.

 

Current is the rate of flow past a point in space so there isn't really a current potential, only a voltage potential. To solve your circuit, we can model the voltage sources as having a series resistance by using Ohm's law. By starting with voltages and resistances, we can calculate how much current will flow.

Take a look at this LTspice simulation,

1) At node A, we see V1 is supplying 5V and 1A is flowing through R1.

2) At node B, we see V2 is supplying 20V and 50mA is flowing through R2.

2) At node C, we see V1 and V2 are connected therefore 37.03mA flows between R3 and R4. Notice how a positive current flows though R3 and a negative current flows through R4.

Putting this together, we arrive at the proof for circuit C:

(V3 - V4) / (R3 + R4)
(5V - 20V) / (5ohm + 400ohm) = -37.03mA

 

Here is the algebraic equation in the units the question was asked:

?A = (V1-V2) / ((V1/I1) + (V2/I2))

(5V-20V) / ((5V/1A)+(20V/0.05A)) = -37.45mA

The difference between this answer and my first answer (-37.03mA) is due to rounding. The total current will always be less than the maximum of the higher voltage source. In this case, V2 is sourcing 37.03mA and V1 is sinking 37.03mA. V2 can not source more than 50mA but it will source current because the total potential difference (5V - 20V = -15V) develops an electrical field in that direction.

 

There are 2 sources.

Source (A) 5VDC @ Max 1000mA

Source (B) 20VDC @ Max 50mA

If the grounds of both "source(s)" are "common".

Would Pos source (B) flow to Pos source (A)
or
Would Pos source (A) Flow to Pos Source (B) because source (A) has a higher *current* potential?

Other answers have assumed that you have also connected the positive terminals of each source together, but I don't know if that's what you meant or not. Plenty of other people have asked about current flow between batteries that are only connected at a single point. So please be more explicit -- a sketch is always helpful in getting your thoughts across.

 

Other answers have assumed that you have also connected the positive terminals of each source together, but I don't know if that's what you meant or not. Plenty of other people have asked about current flow between batteries that are only connected at a single point. So please be more explicit -- a sketch is always helpful in getting your thoughts across.

I did take a leap of faith on that one but it was still a good exercise.