Hello all, I have a fundamental question regarding batteries/power supplies that I've been wrestling in my hand. Essentially, what I'm stuck on is this- Why can't you create a simple circuit going from the + terminal of a power supply, through a lightbulb, and straight to ground (Earth)? As I understand, current flows when there is a difference in potential between one end of the circuit and the other. So if the power supply is outputting + 10V from its positive terminal and the other end is at ~0V (earth ground), what is stopping current from flowing? I understand that you need a closed loop for current. i.e. a break or "open" circuit will not allow any energy flow through the medium. But in my above example, there isntt technically a break in the loop. Also, I'm assuming its different for batteries as there is a chemical reaction element to the process that requires both ends of the battery to be used. Thanks for the clarification.