In the giancoli physics textbook for engineers and scientists, it says "E=F/q where E is the force on a small positive test charge at rest...." Then about one paragraph later it proceeds to say "If q is positive, F and E point in the same direction. If q is negative, F and E point in opposite directions". I am confused. The text just said that the test charge in the E field equation will always be considered a -positive- charge, but then they talk about scenarios where it is negative, contradicting their own definition. and if a test charge was then (contradicting their definition) negative, and "big" Q is negative, both the e-field and the force would be repulsive, pointing in the same direction whereas they said "if q is negative F and E point in opposite directions" (which would only be true if you assume the direction of the e field -where negative source charge has e field towards it- because you have a positive test charge) I do not understand what I am missing so any help in clarifying this problem would be helpful.