During this lab two types of circuits were made using resistors, soderless breadboards, and DC power supplies. The first circuit had one resistor, and a power supply. The resistance was varied by using different valued resistors in the circuit. The resistors used in this lab were 12k, 120k, and 220k ohm resistors. The second type of circuit had two resistors in parallel wiring, and a power supply. The resistance was again varied by using the resistors mentioned above. The current flow was measured through each circuit while the voltage was varied by 0.5 volts, on the range of -10 volts and 10 volts. The data was recorded and used to analyze the behavior of the circuits.
~Calculations.
The circuits that were created in the lab experiment were simulated in a computer program called PSPICE. This program simulated how the circuits would react under a DC voltage sweep on the range of -10volts to 10 volts. The results were plotted using the measured current as a function of voltage. This was done for each resistor value. The slope of each graph was calculated using the following formula:.
M=y2-y1/x2-x1.
e.g.(12k).
5-0/6-0=.83.
There is, apparently, a linear relationship between the resistance value and the measured current in the circiut, that is to say that current varies directly with resistance in these circuits. .
~Analysis.
This lab experiment demonstrated the relationship between current and voltage in the circuits we constructed. Both the simulated and the actual circuits reacted in a similar manner, which increases our confidance in our results. The graphs clearly shows that the current varies directly with voltage. This was expected because Ohm's law says that voltage is equal to the current times the resistance. Since the resistance was constant in each circuit, the current was determined only by the voltage. This was clearly demonstrated by this lab.
