Thevenin Equivalents

           We were given the engineering problem of finding the smallest equivalent load resistance that can be used in a system of multiple sources and loads. Using Thevenin Equivalent, we wanted to simplify everything into a circuit with only VTh, RTh, and Rload 2. Therefore, using nodal analysis, we calculated Vth = 8.64V and I load 2 = 0.131 A, and found RTh with RTh = VTh/ I load 2 = 66 Ω. With a min. Voltage of 8V across load 2, we used Ohm's Law to find RL2 = 825 Ω.

 

 

              We first built the thevenin equivalent circuit on a breadboard. After measuring values, we treated the RL2 to have infiinite resistance and measured the voltage. The values were as followed:

Config                     Theoretical Value        Measured Value         Percent Error

RL2 = RL2, min          VLoad 2 = 8V                 VLoad 2 = 7.77V            2.9%                

RL2 = ∞Ω                VLoad 2 = 0V                 VLoad 2 = 0V                  0%

 

 

 

       

          Afterwards, we built the original circuit, consisting two power sources and more Rs, and calculated:

Config                     Theoretical Value        Measured Value         Percent Error

RL2 = RL2, min          VLoad 2 = 8V                 VLoad 2 = 8.04V            0.5%              

 

Values were fairly close with both circuits. Percent error may have been the result of using 9.11V for power sources instead of an ideal 8V, and using R's slightly different from nominal values.