How is AC current transmitted through power lines if it changes direction regularly after a half-cycle proportionally in the opposite direction?

Question

How does the current flow in one direction if the electrons are hoping back and forth? Shouldn’t the net current be zero?

In: 3

Answer 1

Have you ever seen a mechanical crank, as in the type you have in crank shafts in engines or the ones seen on the outside of the wheels of steam engines. There is a piston pushing a rod back and forth. You can ask the same question with this, how is the power transmitted through the rod though it changes direction after half a cycle? This is because not only is the direction of movement changed but also the direction of force. The piston is only pushing on the rod when it is moving away and the crank attached at the other end is resisting this motion. But when the rod is moving towards the piston the piston is not pushing or in the case of steam engines it is pulling the rod.

AC current is exactly like the rod in a crankshaft. The movement of the rod is similar to the current in a power line while the force applied through the rod is similar to the voltage of the line. When the current changes direction so too does the voltage. The generator is basically pushing and pulling on the electrons to make sure the current alternates while the appliance is resisting this current. So power is transfered through an alternating current line.