Identify Direct / Inverse Proportions = Solve Proportional Problems
Solve for the quantities (voltage, current, resistance) that make up an electrical circuit.
T-Chart Electrical 46.0399 m11a212 Direct and Inverse Proportions.doc
Although it’s important for students to be able to use Ohm’s Law to solve problems, teaching the direct and inverse proportional relationships helps to deepen their understanding and make problem solving easier. For instance, if the problem on the Electrical side of the T-chart was rephrased to read, “If when the current is equal to 20 amps the resistance is equal to 60 ohms, what would be the resistance value when the current equaled 40 amps?” Students who do not understand the inversely proportional relationship between resistance and current would have to use Ohm’s Law to first solve for voltage and then use the voltage to find the new resistance.