DC Circuits

In this lab you will study how current and voltage changes in simple electrical circuits and inside standard components.

Objective

Predict the voltages across each component and the currents in each branch of the circuit shown in the adjacent diagram, then build it and test your predictions.

Resources

  • two batteries
  • several resistors of different values
  • hook-up wires with clips
  • multimeter

Background

Many circuits can be analyzed through two simple rules known as Kirchoff’s rules. The first of these states that the currents entering and leaving any point in a circuit must sum to zero. The second says that the changes in voltage along a closed path in a circuit must sum to zero. Since the voltage change due to a resistor is the current times the resistance, the unknown values in a circuit composed of resistors and EMF’s can be solved for by writing down several equations according to Kirchoff’s rules and solving for the unknown values.

Guideposts/Hints

  • Make sure you understand how to measure current and voltage with a multimeter.