Nodal Analysis Lab

The Nodal Analysis Lab was designed to familiarize students with real world applications of the Node Voltage Technique. The idea behind it is to build a system which can sustain damage to one part of the circuit without bringing everything offline which has obvious uses in the real world. One simple way to think about how such a task is accomplished is the use of multiple voltage sources and loads. To test this out, students built the following circuit;

 

The following circuit is composed of several resistors which are meant to simulate the loads on a real world circuit. The values of the resistors starting from the left are; 100 , 1000, 220, 1000, and 220 Ohms. They are connected together in several nodes with power supplied from the left and right sides from two separate power supplies. Before building the circuit, students first calculated the theoretical values for the power supplies needed. Using the nodal equations, students were then able to calculate both the corresponding currents and power supplied by both batteries. 

 

Students simply used a 12 and 9 Volt setting respectively. The following is the measured values compared to actual values used.

Component	Nominal Value	Measured Value	Power or Current Rating
R1 (Ohms)	100	99	0.25 W
R2 (Ohms)	220	224	0.25 W
R3 (Ohms)	220	218	0.25 W
RL1 (Ohms)	1000	983	0.25 W
RL2 (Ohms)	1000	989	0.25 W
Vbat1 (Volts)	12	12.12	2 Amps
Vbat2 (Volts)	9	9.09	2 Amps

Here were the measurements taken when compared to the theoretical values.

Component	Nominal Value	Measured Value	% Error
Ibat1	17.5 mA	17.39 mA	0.63%
Ibat2	1.5 mA	1.5 mA	0%
V2	10.25 V	10.35 mA	0.98%
V3	8.67 V	8.75 mA	0.91%

As you can see, the experiment went very smoothly and nothing surpassed 1% error. A system with 2 separate power supplies can remain at least partially function if one is disabled. This measure of reliability is critical to real world applications in which electronic circuits may be subjected to the elements, or a copper tipped explosively formed penetrator punching its way through a military electronics system. By supplying two voltage sources, a system's operational capacity is not bottle necked at simply knocking out the voltage supply. In fact, by varying the voltage settings of the sources, the system can be controlled as demonstrated by the final portion of the lab. In order to get 0 current going across the RC2, a voltage of 9.9 V and 10.98 V are needed for VS1 and VS2 respectively.