Alternating Current Mysteries.

Alternating current behaves quite different from direct current and this seems to be giving false hope to many free-energy tinkerers. Let’s have a look at some of these differences.

The magic usually goes hand in hand with the usage of reactive components, of which there are two types; inductive and capacitive. To keep this post as simple as possible I will only discuss the latter, but similar effects can also be created with inductive components.
A capacitor can best be compared to a rechargeable battery; one that can be charged and discharged in very short intervals. If a capacitor is connected to an AC source, the voltage on the capacitor is constantly changing and in order to do so a current is flowing into the capacitor when the voltage is rising and out of the capacitor when the voltage decreases. Furthermore this current depends on the rate of change in the voltage. In other words, if the voltage changes rapidly a larger current flows.
Back to our capacitor on an AC source, we notice that during half a cycle the current is flowing into the capacitor, while during the other half current flows back to the source.
The same goes for energy, it constantly flows back and forth between the source and the capacitor and so even though a lot of current flows, no energy is consumed, it is taken from the source and returned, taken and returned, etc.
When you connect a (non-digital) KWh meter in between, it produces a loud humming noise but it does not move.

There is a group of free energy tinkerers that believe that if you use the return flow you’ll get the energy for free. But it is easy to understand from the above, that no matter from which flow you take some energy there will be less energy returned to the source and so you will need to pay for the difference.

More complex magic happens when you connect a resistor and a capacitor in series to an AC source, and measure the voltages across these components. You will notice that the voltage across the resistor + the voltage across the capacitor is greater than that of the AC source. This happens because these voltages are out of phase, meaning that when the voltage across the resistor is at its maximum the voltage across the capacitor is still rising. So their maxima occur not at the same time and when you measure the voltage, you measure a value derived from these maxima.
It is this effect in particular that causes a lot of confusion in internet communities, and it is said that this was one of Edisons reasons not to trust AC.

There is no magic however, only misunderstanding. Someone once said that magic is simply science that is not (yet) fully understood.