Engr 201
Thevenin Equivalents:
Purpose:
To verify that, in fact, the concept of Thevenin Equivalent circuits works as advertised.
Procedure:
1) Wire the following circuit on the project board with the power off. After having the circuit verified by the instructor you may turn the power on and begin your measurements. Note that you will be making simultaneous measurements of the load current and the load voltage. Have your DMMs wired into the circuit before approval. Once again careful attention to circuit wiring and organization will pay benefits in the long run.
2) With infinite load resistance (open circuit) determine the potential difference between V1 and V2. Then determine the short circuit current between V1 and V2. Repeat this measurement using a 1 W resistor and determining the current from Ohm’s Law.
3) Calculate the theoretical open circuit voltage and short circuit current.
4) Take at least 4 data points to determine the load curve for the original circuit. You need to choose resistors and determine a reasonable data range.
5) Calculate the Thevenin Equivalent source and Thenvenin Resistance. Wire this equivalent circuit with the appropriate resistance.
6) Verify the open circuit voltage, short circuit current, and the load curve are unchanged.
Lab Notebook:
The following information should be clearly presented in your lab notebook along with explanatory commentary.
I) A clear drawing of each circuit constructed including the DMM as you used them.
II) Measurements of the open circuit voltage, short circuit current (both methods), and the load curve data.
III) Calculations showing the theoretical determination of the Thevenin Equivalents.
IV) Data from your equivalent circuit verifying that the open circuit voltage, short circuit current (both methods), and the load curve data are the same.
