03-17-2016

03-17-2016: Thevenin Equivalent, Norton Equivalent

I. Introduction:

Here was the idea of Thevenin problem- if we changed one component in the circuit, it would make us to redo the whole calculation. The idea of Thevenin is that we can treat part of the circuit we don't need to know, and replace it with a voltage source and a resistor.

Using the everycircuit to check our work, which turned out to be correct

II. Thevenin equivalent concept:

If we just need to focus on element in the circuit (eg a resistor), then we have to redo the calculation for the circuit every time we make that decision,but with Thevenin, founded by Thevenin, a French engineer, we could replace our circuit with a voltage source (or current source if a Norton equivalent) and a resistor.

For thevenin equivalent, to find Vth, we open circuit that branch. To find ith, we short circuit that branch. To find Rth, we could take Vth/ith or we could use the test source method ( for this method, we keep the dependent source, for the independent current source, we open circuit, for the independent voltage source, we short circuit)

Here we were trying to find the Rth. We short circuit the voltage source and open circuit the current source. and find the Rth

II. Practicing finding the Rth equivalent using the combining Requi

We were practicing finding th Rth of the circuit. By following the rules as shown above, it would be faster using this method comparing to find the Isc in thevenin.

III. Power Load Part 1:
1. lab
We obtained many ressitors, to set up the thevenin circuit given by Professor Mason in the lab manual

Before we actually did the work, we checked the perecent error of all the resistors, which usually less than +-5%

We used the everycircuit to check the result of our lab.

Our data for percent comparing between the theoretical result to the experimental results

The formula for P=V^2/R. We used the "pot" to vary our resistance, we found 10 data points and ajjust

Here is our data table, the nax power is associated with the highest power

IV. Conclusion and Summary
For today lab, we spent most of our time learning about Thevenin equivalent, including finding the Thevenin voltage, resistance, and Norton current. We spend the other half of our time doing the lab work to verify with our results. The numbers had some small errors due to the fact that those resistors had their percentage resistance error