Day 5 (Nodal Analysis lab)

You don't need to wait until SUNDAY SUNDAY SUNDAY SUNDAY to learn about super nodes! A super node is actually two nodes that enclose a single voltage source and instead of writing an extra equation for both, the two can be combined and the currents entering that super node equal the currents exiting the super node. This technique was applied to a circuit and the arbitrary vx was equal to 30 volts.

The Nodal Analysis lab was just to experimentally prove that this technique does work and will give a correct interpretation of the circuit. In the pre-lab a circuit was analyzed using the nodal analysis technique. The voltages vary based on how much uncertainty the resistors have.

The circuit was then built and the experimental voltages were compared against the theoretical voltages. The experimental voltage drops for the 6.8 kiloohm and 22 kiloohm resistors were 2.43 and 4.41 volts respectively with percent errors of .413% and .22% respectively. Here are pictures of the circuit, the data, and the calculations.

The next circuit analysis technique that is introduced is mesh analysis. The concept is simple, each loop has some arbitrary loop current and then KVL is used to analyze the loop taking into account each of the arbitrary currents that affect each element in that loop. (I love this technique!)

This circuit was analyzed using mesh analysis and the loop currents were 1 amp and -2 amps, meaning that the direction was incorrect.