ENGR 225 Circuit Analysis                          Name_________________________

Lab #1 - Lab Familiarization and Voltage,   Date__________________________

Current, and Resistance Measurements



To become familiar with the lab station and the operation of some of the equipment.

To make voltage, current, and resistance measurements.

To verify Kirchhoff’s voltage and current laws and Ohm’s law.

To demonstrate the application of the voltage divider and current divider equations.



1.  A) Inventory the equipment found at your lab station - equipment type, make, and model #.          B) Learn how the resistors are organized in the top two rows of drawers in your parts cabinet.                  Make a sketch to convey what you have learned. 

     C) List the standard values that are available in the lab over the decade of resistance from 1kΩ         to 10kΩ.


2. A) Learn the resistor color code for the 4-band +5% resistors we have in the lab.  Use the                information on the blackboard to help you. 

    B) Then pick one resistor at random from each drawer.  Determine its resistance from the color of the bands. 

    C) Next, measure the resistance with the DMM.  Record the color code, the determined           resistance, and the measured resistance for each of the six resistors. 

    D) Finally, mix up the resistors and by looking at the color code put them back in the right      section of the drawer where they belong. 


3. A) Use the DMM to measure the voltage between each set of the three terminals of your            power supply. 

    B) From your measurements determine how the power supply works and what the maximum     and minimum possible voltage output values are.  Also, learn the significance of the digital readouts on the front of the power supply. 

    C) Report what you have learned.


4. A) Connect the #1819 incandescent lamp given you across the voltage from the power supply,   and as you vary the voltage from 0 to 28V, record the voltage across the lamp and the current through the lamp at 2V increments. 

    B) Plot a curve showing the current as a function of voltage.  What is the significance of the      slope of this curve?  How does this relate to Ohm’s law? 

    C) Repeat this procedure using a 560Ω resistor with a 2W power rating.  Comment on the fact    that some resistors are linear and some are nonlinear.


5. A) For the circuit shown in Figure 1 take measurements of the indicated voltages and currents.     B) Demonstrate Kirchhoff’s voltage and current laws using these measurements.

    C) Demonstrate current division of i1 (through R1) by the branches R2 and R3. 

    D) Calculate an equivalent resistance for R2 and R3 and demonstrate voltage division of the      applied voltage by R1 and this Req. 

    E) Report all of your measurements and calculations and summarize your findings.








Figure 1.  Measure voltages and currents in this circuit..