University of Bahrain College of Applied Studies EEA111 – Electrical Technology E xperiment 3 Series Resistanc and Kirchhoff’s voltage law Objective: • • • • • Equipment: • • • Determine the total resistance of series and Parallel dc circuit using an ohmmeter or an application of ohm's law Calculate the total resistance of a series and Parallel dc circuit and note the effect of the relative magnitude of each series and Parallel on the total resistance Learn to identify which resistors and Parallel of a network are in series Determined the current in each circuit element Determined the voltage in each circuit element Resistors 100 Ω,220 Ω , 330 Ω , 1K Ω , 100K Ω DC Power Supply Malta meter Theory The total resistance Rt of a series circuit is the sum of the individual resistances For equal series resistors, the total resistance is equal to the resistance of one resistor times the number in series For any system , the total resistance can be determined by the following form of ohm's law: 1 University of Bahrain College of Applied Studies EEA111 – Electrical Technology That is for an applied voltage E the current is measured and is applied to determine the resistance of the network In a series circuit, the current is the same through the entire circuit element By ohm's law, the current I is = E/RT, where E is the impressed voltage and Rt the total Resistance Kirchhoff’s voltage law states that around any closed Path in a n electric circuit , the algebraic sum of all the voltage drops must equal the algebraic sum of all the voltage rises , this means that that the sum of the voltage drops across the series resistors must equal the voltage applied across the series resistance combination .therefore, using Kirchhoff’ voltage law and ohms law V = V1+V2+V3 Where V1= (I)(R1) , V2= (I)(R2),and V3= (I)(R3) Part 1-1 Two Series Resistors 1- Construct the Circuit R1 measured = _________ R2 measured = __________ 2- Measure the total resistance RT measured =_________ 3- Calculate the total resistance RT calculated= 4- How do the measured and calculated values compare? Calculate the magnitude of the percent difference from measured − Calculated × 100% Calculated _____________________________________________ % Difference = 2 University of Bahrain College of Applied Studies EEA111 – Electrical Technology 5- Set the Supply to 8 V , find the following VR1 VR2 IS Part 1-2 Three Series Resisteors 1- Construct the Circuit R1 measured = _________ R2 measured = _________ R3 measured =_________ 2- Measure the total resistance RT measured =_________ 3- Calculate the total resistance RT calculated= _____________________________________________ _____________________________________________ 4- How do the measured and calculated values compare? Calculate the magnitude of the percent difference from measured − Calculated × 100% Calculated _____________________________________________ % Difference = _______________________________________________ _______________________________________________ 3 University of Bahrain College of Applied Studies EEA111 – Electrical Technology 5- Set the Supply to 8 V , find the following IS VR1 VR2 VR3 IS Part 1-3 6- Using the supply voltage and ammeter reading from step 5 , calculate the total resistance using Eq _____________________________________________ A Composite 1- Construct the Circuit R1 measured = _________ R2 measured = _________ R3 measured =_________ R4 measured =_________ R5 measured =_________ 2- Measure the total resistance RT measured =_________ 3- Calculate the total resistance RT calculated= ____________________________________________ 4 University of Bahrain College of Applied Studies EEA111 – Electrical Technology 4- How do the measured and calculated values compare? Calculate the magnitude of the percent difference from measured − Calculated × 100% Calculated _______________________________________________ _______________________________________________ % Difference = 5- Set the Supply to 8 V , find the following VR1 VR2 VR3 VR3 VR3 IS Exercises 1. Which resistors of next figure are in series? 2. Given the voltage level of next figure , determine the total resistance RT , of the system and the resistance of the container , RT , show all calculations 5 University of Bahrain College of Applied Studies EEA111 – Electrical Technology 3. Given the information appearing in next figure , determine the resistance R2 6