D9 - MAX Power Applications Source Modeling

We started the day with talking about power and how gasoline production has increase over the years. We started with maximum power transfer to a load. And was ask to use the formula P = i^2Rload. We draw the graphs Power versus resistance.

The use of max power transfer when Rth = Rload.

White Board work of getting the formula result for Rth = Rload

We then also came to the conclusion of Pmax = Vth^2/4Rth, only when Rload = Rth.
Afterwards We were asked to do an example.

White boar work to find Rth

White Board work, Rth was found out to be 12 and then found out max powers with different Rload's. Max is achieved when RL 12 is the same as Rth which is 12.

We then moved on to a motor example showing how the motors can get max power.

White Board work of the motors each one being in parallel.

More Whit Board work with us finding Rth = 0.052 ohms.

Last bit of White Board work, we used the V^2/4Rth since RL is = Rth.  Answer is 5.8A hours.

We then movd on to another max power transfer example.

White Board work, we remove the Rload and found Req = 9 ohms.

More White Board work with Vth = 22 Volts and getting isc = be 22/9 or 2.4 A.

After our last class example we moved onto the lab.
Maximum Power Transfer:

Picture of our ciruit with a Pot and Rload.

White Board work, R = 4.64K ohms. Diagram of circuit at top and Vout data at the bottom.

Picture of graphing Power and Resistance. Note the max when Rload = Rth.

Right side of the Graph of Power versus Resistance.

More data used, from R being 1k to 10 k, max power is when Rload is = Rth of 4.64 k ohms. 

 

We then finished the class with talking about source modeling and how a DMM Galvanometer read current and resistance. Lastly we did an example to find out Vout.

White Board work to find Vout = 12.29 Volts across terminals a,b.

In summary we learned about how and why maximum power transfer if done when Rth = Rload. We talked about the steps needed to find Req and then did a lab on maximum power transfer. We showed that with the measurements that when Rth = Rload the graph was at it's peak. Lastly we finished the class with talking about source modeling and how DMM's and Galvanometer take readings. We finished the class with last example of finding Vout in a circuit.