I am trying to solve the following simple circuit to obtain the current flowing through the 5V source. The answer I obtain does not agree with a simulator that I am using, and I think it's because I assume the wrong direction for current through the 19k resistor... Using conventional current flow, here is my approach to the problem:
Calculate the current through the 19k resistor as just 5V over 19k and I get 263uA. I then calculate the current through the 300k resistor as just 20V over 300k. I assume that the current is flowing in from the 5V source and also in from the 19k resistor and outward through the 300k resistor. Therefore using KCL I get:
(current through 19k) + (current through 5V) = current through 300k
263uA + I = 66.67uA
I = -196uA
However when I use the simulator at falstad.com/circuit/ I get a different result. I get like 329uA. Does it actually matter which direction I assume the current is flowing in? Or, is it that maybe the drop across the resistor is actually -5 because of the polarity on the voltage source?