Lab 4 - Nodal Analysis

In this lab we investigated the procedures of nodal analysis by using them to analyze more complex circuits.  Since these procedures are an invaluable tool for analyzing circuits which contain multiple power supplies and multiple loads, we created a complex circuit in order to evaluate them.  The idea was to construct a circuit with more than one power supply so that we ensure a reliable power source.  The circuit constructed contained two voltage sources(12.2V, 9.12V), two loads(994|994ohm), and 3 cable resistances(98.5|218|220ohm).  We were able to calculate theoretical values for the current coming from the power supplies and the voltages across the loads and then compare these to our measured results.  We found that the percent error between these was less than +/-2% in all cases which validates the node method. 

Variable	Theoretical	Measured	% Error
I bat1	0.0175	0.01732	-1.02
I bat2	0.0015	0.00151	-0.667
V2	10.25	10.4	1.46
V3	8.67	8.8	1.5

Lab 3 - Voltage Dividers

In this lab we investigated the effects that multiple loads have on a circuit and in particular the effects that they have when used in conjunction with an unregulated power supply.  Since switching multiple loads on/off in a circuit causes the voltage in an unregulated power supply to swing up and down, we attempted to design a circuit that would only have a voltage swing of +5% or -5% from 5V.  Knowing that we were to have 3-1000ohm resistors hooked up in parallel for our various loads, we were able to calculate what the optimum voltage and resistance of the supply should be to stay within this +5|-5 range(V=5.54 & R=55.6ohm).  Then, we hooked up the circuit and tested the actual loads to see how close we came.  Our voltage swung 1.73 to 12.98%.  This difference is likely due to the fact that our voltage was 6.05V rather than the true 5V supply desired and also because we used stock resistors which varied slightly from 1000ohms.  

Lab 2 - Introduction to Biasing

In this lab we attempted to bias circuit components so that they operate at their correct voltages and currents.  Our experiment involved biasing two different diodes which we ran parallel to each other and powered with a 9V power supply.  Since the diodes operated at different specs, an appropriately calculated resistor was found and added in series with each diode to ensure that it received the necessary voltage and current.  For the yellow and red diodes, we found that ~150 and ~360 ohm resistors were required respectively.  In the real world, since various components operate at different specs, care needs to be taken in the design of the circuit so that they operate properly.        

Lab - Introduction to DC Circuits

In this lab we investigated DC circuits and the added resistance that exists in wires.  The idea was to set up a simple circuit with a power supply and load, and then use a variable resistor box to simulate the effects of long cables in a circuit.  We found that additional cabling(variable resistor box) draws additional power that would increase the rate of discharge of a battery(power supply).  Thus, since resistance R is proportional to the length of wire, a longer wire will consume more power due to the relationship P=I^2R=V^2/R.