In an ac circuit the polarity of the voltage source changes periodically. So too will the current. However my circuit course has the voltage source labelled with a positive and negative as seen in the schematic below:
This software used to draw the schematic also provides the voltage source icon with the positive and negative signs on it. Using the polarity of the source we can draw the direction of current flowing towards the resistor in the loop. My main source of confusion is that ac alternates the direction of current therefore why do we draw current in one direction and polarise the sources?