The relationship between power, circuit current and resistance ，depicted by a function graph.

The relationship between power, circuit current, and resistance can be described by the following equation:

P = I^2 * R

Where P is power in watts, I is current in amperes, and R is resistance in ohms. This equation can also be rearranged to solve for any of the variables.

If we plot this equation on a graph, we will see a quadratic curve that represents the power output of a circuit as the current and resistance change. As the current increases, the power output of the circuit increases exponentially. However, as the resistance increases, the power output decreases exponentially. This is because the resistance acts as a limiting factor on the flow of current through the circuit.

Overall, the graph of this function shows that there is an optimal point where the circuit is most efficient, maximizing the power output while minimizing the current and resistance.