Introduction to Circuits and Ohm's Law
Students explore the basics of DC circuits, analyzing the light from light bulbs when connected in series and parallel circuits. Ohm's law and the equation for power dissipated by a circuit are the two primary equations used to explore circuits connected in series and parallel. Students measure and see the effect of power dissipation from the light bulbs. Kirchhoff's voltage law is used to show how two resistor elements add in series, while Kirchhoff's current law is used to explain how two resistor elements add when in parallel. Students also learn how electrical engineers apply this knowledge to solve problems. Power dissipation is particularly important with the introduction of LED bulbs and claims of energy efficiency, and understanding how power dissipation is calculated helps when evaluating these types of claims. This activity is designed to introduce students to the concepts needed to understand how circuits can be reduced algebraically.
Students explore circuits and Ohm's lawCopyright 2009 Washington State University
Ohm's law (V=IR) is a key equation in the analysis of electrical circuits since it relates the voltage (V) to the current (I) scaled by the resistance (R). So the resistance, R, is a measure of the potential difference V divided by the flow of charge or current I. It is important to remember that the resistance is typically a function of the temperature. Electrical engineers use this equation constantly to guide the design of electrical systems. Students need a strong foundation in Ohm's law while designing circuits on their own.
After this activity, students should be able to:
- Measure the DC current in a circuit (DC stands for direct current, the type of current supplied by batteries).
- Measure the DC voltage across an electrical component.
- Calculate the power dissipated by a DC electrical component.
- Describe the difference between a series and parallel connection.
- Provide at least two examples of how electrical engineers use these concepts.