In my diagram I have a positive source charge Q. I would like to compare the difference between how positive test charge A and negative test charge B respond to the Electric field created by Q. Let's ignore the effects of A and B on one another. Positive test charge A moves away from Q, and as it does so it's electric potential V decreases. Negative test charge B moves toward Q, and as it does so it's electric potential V increases. This is the point that I am confused on. In both cases, the electric potential energy decreases, as A moves farther away from Q and B moves towards Q. Is the movement from lower to higher electric potential for the negative test charge just a result of the convention used in defining electric potential? Is the fact that potential energy is decreasing in both instances the important point to note?