The Different Characteristics of a Voltage and Series Circuit in Regard to Current and Voltage of the Circuits - Lab Report Example

Lab Report The aim of the experiment was to determine the different characteristics ofa voltage and series circuit in regard to current and voltage of the circuits. The experiment was set up so as to determine whether and how different is the voltage and current in a parallel and a series circuit. The aim was achieved by setting up a parallel circuit and a series circuit using the same voltage sources, then taking measurements of the current and voltage in the two circuits. It was established that indeed there is a difference in the characteristics of a voltage and series circuit in regard to current and voltage of the circuits. Current is constant in a series circuit while voltage is constant in a parallel circuit (ANWAR, HALL, PRASAD and ROFFEY,1998). Introduction Voltage is defines as the measure of the potential difference between two terminals in an electric circuit or electric apparatus. Current is defined as the flowing charge in an electric circuit or electric apparatus. Resistance is the measure of the tendency of an electric apparatus to hinder electric charge from flowing through a given circuit (NAHVI and EDMINISTER 2004). A series circuit is one in which the positive terminal is connected to the negative terminal of the circuit. Any gap that is induced in a series circuit, by say the break-down of a given apparatus in the circuit hampers electric charge from flowing in the entire series circuit. A parallel circuit is one in which at some terminals of the circuit, positive terminals are connected to other positive terminals and negative terminals are connected to other negative terminals. In this regard, a gap introduced at a given point of the circuit does not get the electric flow of charge in the entire circuit to stop. In a series circuit, the current at any point of the circuit is the same for the whole circuit. This is unlike the case in a parallel circuit where the current at one point of the circuit is not necessarily the same as the current in the other points of the circuit (SCIENCE AND TECHNOLOGY FOR CHILDREN, NATIONAL SCIENCE RESOURCES CENTER, NATIONAL ACADEMIES and SMITHSONIAN INSTITUTION, 2004). The voltage in a parallel connection is limited to that of the smallest voltage source connected in the circuit. On the contrary, in a series connection, the voltage of the circuit is determined by the number of the individual voltage sources connected. The more they are connected, the higher the circuit voltage gets. Kirchhoff’s 1st law implies that the sum of all the current that is entering a given point or junction in an electric circuit has got to be equal to the sum of all the current that is leaving that particular junction. Kirchhoff’s 2nd law implies that in considering an electric loop, all rises in the voltage have got to be equal to all the drops in the voltage around the loop (NAHVI and EDMINISTER, 2003). Ohms law implies that there is a direct proportionality between the current flowing in a circuit and the voltage in the circuit (ANWAR, HALL, PRASAD and ROFFEY,1998). The constant of proportionality is the resistance of te circuit. In that regard, the equation of Ohms law is V=IR; where V-Voltage I- Current and R-Resistance Method The series circuit was connected as shown in the diagram below. The voltage source was connected as shown and its value was 15V The parallel circuit was connected as shown in the diagram below. The voltage source was connected in the terminals (a)-(b). and its value was 10V Results Series Circuit Nominal Resistance (Ω) Measured Resistance (Ω) % Difference R1 = 680 671 1.3% R2 = 1000 978 2.2% R3 = 820 810 1.2% Rtot = 2500 2466 1.4% Table R1 Quantity Measured value from DMM Theoretical predictions % Difference Vs 15V 15V 0 Rtot 2466Ω 2500Ω 1.4 VR1 4.1V 4.12V 0.5 VR2 5V 4.97V 0.6 VR3 5.99V 6.07V 1.15 IA 6.075A 6A 1.25 IB 6.075A 6A 1.25 IC 6.075A 6A 1.25 ID 6.075A 6A 1.25 Table r2 Parallel Circuit Quantity Measured value from DMM Calculated Values Vs 10.1V 10V VR4 10.1V 10V VR5 10.1V 10V VR6 10.1V 10V IA 37.2mA 36.9mA IB 10.24mA 10.5mA IC 12.38mA 12.19mA ID 14.99mA 14.7mA Rtot Table R3 Discussion Series connection From the results, it is evident that indeed in a series connection, the current in the circuit is constant regardless of the resistance and voltage of the circuit. The voltage changes from point to point, and in essence current is directly proportional to voltage at all points. That conforms to the Ohms Law. The voltage drop within the loop is equal to the voltage gain in the loop which in essence also conforms to the Kirchhoff’s 2nd Law (DORF and SVOBODA, 2006). The percentage difference between the total nominal resistances and total measured resistances comes into play based on the fact that measuring instruments may have some slight errors such as the zero error. The measuring process itself may also lead to the difference. There might be some error such as parallax error during the measuring process which accounts for the overall difference. The differences are also caused by the resistances of the conductors which are small but measurable (NATIONAL SCIENCE RESOURCES CENTER, SMITHSONIAN INSTITUTION, NATIONAL ACADEMY OF SCIENCES, CAROLINA BIOLOGICAL SUPPLY CO. and SCIENCE AND TECHNOLOGY FOR CHILDREN,2005). The measured potential differences are slightly less than the theoretical potential difference. The measured Current are slightly more than the theoretical ones. The differences are due to the fact that measuring instruments may have some slight errors such as the zero error. The measuring process itself may also lead to the difference. There might be some error such as parallax error during the measuring process which accounts for the overall difference. The differences are also caused by the resistances of the conductors which are small but measurable (NAHVI and EDMINISTER 2004). Parallel circuits In parallel circuit, the value of the voltage across the circuit is constant regardless of the resistance and the current across the lines. It is also apparent that the sum of all the current that is entering a given point or junction in the circuit is equal to the sum of all the current that is leaving that particular junction. This conforms to Kirchhoff’s 1st law. The current flowing through any line of the circuit is directly proportional to the voltage of the circuit and the constant of proportionality is the resistance. That conforms to the Ohms law (NAHVI and EDMINISTER, 2003). The measured resistances are slightly more than the theoretical resistance. The differences are due to the fact that measuring instruments may have some slight errors such as the zero error. The measuring process itself may also lead to the difference (DORF and SVOBODA, 2006). There might be some error such as parallax error during the measuring process which accounts for the overall difference. The differences are also caused by the resistances of the conductors which are small but measurable. One of the improvements that may be done is checking the instrument for any errors. It would be good to have all the instruments being absolutely error free. Another improvement is ensuring that the measuring process is done very carefully and with precision. Any errors made during the measuring process would be eliminated. Another improvement is using conductors that are free of resistance. The experiment has made it clear that indeed there is a difference in the characteristics of a voltage and series circuit in regard to current and voltage of the circuits. Current is constant in a series circuit while voltage is constant in a parallel circuit. The experiment has made it clear that indeed The Kirchhoff’s 1st Law and 2nd Law are true. It has also proven that the Ohms law is true as well. Bibliography NAHVI, M., & EDMINISTER, J. (2004). Electric circuits. New York, McGraw-Hill. ANWAR, M., HALL, T., PRASAD, N. R., & ROFFEY, L. E. (1998). Electric circuits. Lincolnwood, Ill, NTC LearningWorks. DORF, R. C., & SVOBODA, J. A. (2006). Introduction to electric circuits. Hoboken, NJ, J. Wiley & Sons. NAHVI, M., & EDMINISTER, J. (2003). Schaums outline of theory and problems of electric circuits. New York, McGraw-Hill. SCIENCE AND TECHNOLOGY FOR CHILDREN (PROJECT), NATIONAL SCIENCE RESOURCES CENTER (U.S.), NATIONAL ACADEMIES (U.S.), & SMITHSONIAN INSTITUTION. (2004). Electric circuits. Washington, D.C., National Science Resources Center]. NATIONAL SCIENCE RESOURCES CENTER (U.S.), SMITHSONIAN INSTITUTION, NATIONAL ACADEMY OF SCIENCES (U.S.), CAROLINA BIOLOGICAL SUPPLY CO. (U.S.), & SCIENCE AND TECHNOLOGY FOR CHILDREN (PROJECT). (2005). Electric circuits. Burlington, N.C., Carolina Biological Supply Co. Appendix Calculations for table R1 % Difference (680 – 671)* 100/680= 1.3 (1000 – 978) * 100/1000= 2.2 (820 – 810) * 100/820= 1.2 (2500 – 2466) * 100/2500= 1.4 Calculations for table R2 (15-15)*100/15=0 (2500-2466) *100/2500=1.4 (4.12-4.1) *100/4.12=0.5 (5-4.12) *100/5=0.6 (5.99-4.97) *100/5.99=1.15 (6.075-6.07) *100/6.075=1.25 (6.075-6) *100/6.075=1.25 (6.075-6) *100/6.075=1.25 (6.075-6) *100/6.075=1.25 Calculations for table R3 RA = 10/0.0369= 271.0027100271003 RB= 10/0.0105= 952.3809523809524 RC= 10/0.01219= 820.3445447087777 Read More