Week 5 day 1 (Thevenin's Lab)

Lecture

The first activity that we do in the class is using source transformation to find Thevenin Resistance and Thevenin's voltage source.

 Our group decided to use source transformation method to solve this problem. We calculated Thevenin resistance of 20 Ω and Thevenin Potential of 40 V. In our next activity We are calculating the maximum power output of a circuit by calculating Thevenin potential and Thevenin resistance. A circuit with that consist of an adjustable load resistance and a Thevenin counterparts reached it's maximum power output when the value of load resistance is equal to its Thevenin resistance.

We calculated a Thevenin resistance of 12 Ω, Thevenin voltage of 40 V and maximum power output, when the load resistance is equal to 12 V, of 33.33 W. tHe third activity of the day is to convert Thevenin potential and Thevenin resistor to it's current counterpart, Norton's current and Norton's resistor. In order to do this, we calculated the Thevenin potential and resistance and used source transformation to convert it to Norton's current and resistance.

Thevenin Lab 

We calculated The theoretical value of Thevenin potential and resistor. 

We calculated Thevenin Resistance of 7.7 kΩ and Thevenin potential -.456 V. We then used easy circuit to simulate our Thevenin equivalent resistor and Thevenin potential.

We shorted the independent voltage source and measured equivalent resistant of 7.7 K.

 We  measured 457 mV of potential difference in our simulation circuit.. since our calculated Thevenin voltage and resistor checks out, we started our Lab:

First, we measured each of our resistors by using DMM :

Below is the table with measured values of each resistor:

Next, we assemble our circuit and measured the open circuit voltage  to find the Thevenin voltage: 

We measured .460 V across the two open circuit. We then shorted the independent voltage source to measure the Thevenin resistor:

Here we measured Thevenin resistor of 7.81 KΩ. Next, we used potentiometer to create a thevenin Equivalent Circuit :

************************************gotta do it someday *****************************************

Next, we used our first circuit and connected the two open terminals to a potentiometer.

We Then measured the potential difference across this potentiometer. we then calculated the power running through the potentiometer using equation

where Vp is equal to the voltage across potentiometer, and Rp equals to resistance the of potentiometer. We then recorded multiple valuse of P and Rp and sketch the function :

Using Matlab we can model this Curve to find Its Maximum Power and the load resistance(potentiometer resistance needed to get there:

Summary :

Finding Thevenin equivalent circuit and Norton equivalent circuit is advantageous if we want to measure  Power and current that flows through anon fixed load resistance. We can find Thevenin equivalent circuit by substituting the fixed component of the circuit with and equivalent Thevenin resistor and a voltage source. To find the value of Thevenin voltage source we simply find the potential difference across the open circuit of the fixed part of the circuit. To calculate the Thevenin resistance we shorted all the independent sources and simply measured the resistance equivalent. We can calculate the power of load resistance by multiplying the load resistance by the square of current passes through the load resistor. Maximum power output by the circuit occurs when the value of load resistor is equal to Thevenin Resistor.