What is the electrical pie chart?

I believe it is the circle with a horizontal line splitting it in half. Then a vertical line splits the bottom half evenly into quarter circles. In the top half is an E (or V), which represents voltage. Then in lower left is I, representing current. In the lower right is R, representing resistance.

It is an easy way to remember Ohm's Law: If you want to find E (electromotive force) [or V for voltage], then look at the chart: I and R are at the same level, so multiply them: E = I*R.

If you want to find current (I), then look and E is above R, so I = E/R. Same for finding resistance. E is above I, so R = E/I. There is also a Pie chart for Power. See related link (below).