Experiment 5: Thevenin Equivalents

Introduction:
     Thevenin Equivalents help us to model linear circuits as a single resistor and power supply. We performed an experiment that proves the validity of Thevenin equivalent circuits.
Objective:
     Test a complicated circuit and measure voltage and current readings through a load, then replace with the thevenin equivalent circuit and measure the voltage and current readings Analyze and interpret the data and perform any error analysis if necessary.

Procedure:
   

This is our original circuit diagram We decided to perform some calculations to find thevenin voltage and resistance.

V1 = V2 = 9V ; Cable 1 (C1) = 100 Ohm ; Cable 2 ((C2) = 39 Ohm ; Cable 3 (C3) = 39 Ohm ; Load 1 (L1) = 680 Ohm ; Potential drop across Load 2 = 8V

Thevenin Voltage = 

Thevenin Resistance / Norton Current

Now that we figured out our thevenin voltage and current, we consider multiple situations for the thevenin circuit.

Required resistance for a potential drop of 8 volts (minimum resistance)

Current through the thevenin equivalent circuit with no load.

Potential drop through load with infinite resistance.

Our Resistors

Setup with resistor boxes

Resistor box and power supply measurements for the thevenin equivalent, theoretical vs actual

Measured voltage vs Theoretical Voltage through the Potentiometer

The results seem to match our predictions on paper within reasonable uncertainty taking into account the differences in our theoretical to actual measurements.

We use the same materials, but with more wires and other necessities for the unthevinized circuit.

Resistor and voltage measurements for our un-thevinized circuit.

The results

The potential drop through the load and also the current matches with our thevenin circuit.


Finally, we will verify that the power supplied is maximized by the formula P = Vth^2/4Rth

Conclusion: The thevenin equivalent allows us to lessen our troubles in calculation when we plug things into a linear ciruit.