D6 - MESH ANALYSIS and Transistors

We started the day with a quiz that required the usage of mesh. We broke apart the circuit into 3 loops and use math matrix to solve. We then talked about which tools are useful for circuit analysis and the white board.

Why choose Node: When Voltage source is easy, and is in parallel. When current source is easy, and is in series.

We then moved onto a circuit example in class. White board work shown later. We then moved onto the lab.
Nodal Analysis Multiple Source 2:
Prelab: White board work, with predictions.

White board work of schematic and prediction values.

Picture of the circuit on breadboard.

White board with real resistors values and prediction of current. Our percent error was little over 10% since we used a 22k ohm resister instead of a 20k resistor, and over all each resistor was a few ohms below rated.

We then talked about diodes and how they are a PN junction and have polarity. They have a drop of 0.7V to bypass the "gap". We then talked about a transistor. They are two types PNP and NPN. Each having a CBE, NPN are activated with postive voltage on B. PNP are activated with a negative voltage on B. Each flow must be greater than 0.6V to run a transistor. We then talked about BJT.
Ic = alpha*Ie, Ic = beta*Ib; alpha = 0.98 to 0.9999 beta = 50 to 10000
Ie = (1+beta)Ib and beta = alpha/(1-alpha)
We then worked out an example.

We transformed the transistor into equivalent circuit.

We then moved onto the last of the day.
A BJT Curve Tracer:
We followed the instruction of the lab. Pictures are not available currently.

Values calculated for the circuit.

BJT graphs, note the gummel to the left.

Matlab work needed.

Wave forms being feed from diligent.

White board work we did earlier.

White board work done earlier in class.

In summary:
We started the day with a quiz, learn what technique to use when, series use mesh, parallel use node. We then tried out our circuit analysis on a lab to see if we got the same numbers, which we did. We the talked a good amount on diodes and transistors and BJT. They all involve doping, and a minimum of 0.6V is needed to by pass that. Two types of transistors NPN and PNP, NPN is preferred. Lastly we move onto BJT gummel plot lab. Which we did and agreed with data sheet.