Electrical Laboratory, Lab Reports of Electrical Engineering

Download Electrical Laboratory and more Lab Reports Electrical Engineering in PDF only on Docsity! Property of and for the exclusive use of SLU. Reproduction, storing in a retrieval system, distributing, uploading or posting online, or transmitting in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise of any part of this document, without the prior written permission of SLU, is strictly prohibited. 30 Experiment 5 SERIES-PARALLEL CIRCUIT At the end of this experiment, the student should be able to: TLO 1: Demonstrate how to measure the voltage and current in a series-parallel circuit using VOM. Solve required quantities by analyzing the circuit diagram. INTRODUCTION: Most circuits in commercial and industrial electronics equipment are combinations of series and parallel circuits. These are referred to as series-parallel circuits and they range from simple resistive circuits to complex networks. The rules for solving a series- parallel circuit are a combination of the rules used to solve series and parallel circuits separately. All circuits, whether the components are arranged in series, parallel, or combinations of series parallel, appear as a single load to the power source. During your investigations into series and parallel circuits, whether you realized it or not, you combined individual resistances into what was seen by the power source as a single resistance. Although series-parallel circuits are somewhat more complex, the procedure is the same; keep combining resistances until a single resistance,RT, is a determined which represents the total circuit resistance. Consider the circuit shown in Fig. 9-1. (a) where resistors R1 and R2 are in series with the parallel circuit consisting of resistor R3 in one branch and resistors R4 and R5 in series in the other branch. To produce any circuit to a single representative resistance, you start with the components farthest from the power source; in this case, resistors R4 and R5. Because they are in series, they must be added. The circuit is redrawn in (b) next step is to calculate the equivalent resistance of R3 and R4 + R5 in parallel. The circuit, shown in (c) is now a series circuit consisting of resistors R1, R2 and Requivalent. Adding these resistances gives you the single resistance, RT, seen by the power source and shown in (d). Property of and for the exclusive use of SLU. Reproduction, storing in a retrieval system, distributing, uploading or posting online, or transmitting in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise of any part of this document, without the prior written permission of SLU, is strictly prohibited. 31 R1 R3 10 R2 6 6 R4 20 R5 20 RT RT R1 6 R2 6 R3 10 R4 & R5 40 R1 6 RT RT RT 20 REQUIVALENT 8 R2 6 (a) (b) (c) (d) Fig. 5-1. ENGAGE 1. How do series circuits and parallel circuits affect the voltage and current in the circuit elements and how does it compare to a combination series-parallel circuit? 2. What advantages does it give over a pure series or pure parallel resistive circuit? EXPLORE 1. Refer to this module and read in advance to have a better understanding of the activities to be performed. 2. Read about Series-Parallel Circuits using the references stated at the end of this module. EXPLAIN & ELABORATE EQUIPMENT/ MATERIALS NEEDED: Power Source - 0 – 20 Vdc, 10 mA Milliammeter - 0 – 10 mAdc Electronic VOM Practical Electronics Trainer R1 - 1 kΩ, 1 W R2, R3 - 1.5 kΩ, 1W R4, R5 - 3.3 kΩ, 1W R6, R7 - 10 kΩ, 1W Property of and for the exclusive use of SLU. Reproduction, storing in a retrieval system, distributing, uploading or posting online, or transmitting in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise of any part of this document, without the prior written permission of SLU, is strictly prohibited. 34 EBC = ___________________________________ = __________ Vdc f) Calculate the voltage across terminals C and D. ECD = ___________________________________ = __________ Vdc 4. a) Adjust the power source to 15Vdc. b) Close switch S1 and measure the circuit current. I = 3.4 mAdc c) Does this agree with the current value calculated in Procedure 3? ________ d) Measure voltages EAB, EBC and ECD, using the dc voltmeter function of the Electronic VOM. EAB = 3.5 Vdc EBC = 5.22 Vdc ECD = 5.8 Vdc e) Do these voltages agree with those calculated Procedure 3?________ f) Open switch S1 and return the voltage to zero. 5. a) Connect the circuit in Fig. 5 – 4. Do not apply power at this time! b) Calculate the equivalent resistance between points A and B. Show your work. RAB = ___________________________________ = __________ Ω c) Calculate the equivalent resistance between points C and D. RCD = ___________________________________ = __________ Ω mA 15Vdc S1 + - 0 – 10mAdc + - R1 1K R2 1.5K R3 1.5 R4 3.3K R5 3.3K R6 10K R7 10K C D A B Fig. 5 – 4 Property of and for the exclusive use of SLU. Reproduction, storing in a retrieval system, distributing, uploading or posting online, or transmitting in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise of any part of this document, without the prior written permission of SLU, is strictly prohibited. 35 d) Calculate the total resistance seen by the power source. RT = ___________________________________ = __________ Ω 6. a) Calculate the current flow through the milliammeter for an applied voltage of 21 Vdc using Ohm’s Law. I = ___________________________________ = __________ mAdc b) Calculate the voltage across resistor 𝑅1. ER1 = ___________________________________ = __________ Vdc c) Calculate the voltage across points A and point B. EAB = ___________________________________ = __________ Vcd d) Calculate the voltage across points C and D. ECD = ___________________________________ = __________ Vcd e) Record your calculated current and voltage values in Table 5 – 1. 7. a) Adjust the power source to 21 Vdc. b) Close switch S1, and measure the circuit current. I = 2.8 mAdc c) Measure voltages ER1, EAB, and ECD. ER1 = 2.8 Vdc EAB = 2.9 Vdc ECD = 14.7 Vdc d) Record the measured current and voltage values in Table 5 – 1. I ER1 EAB ECD CALCULATED MEASURED Table 5 – 1 e) Return the voltage to zero. f) Do the measured values agree with the calculated values? __________ g) List three factors that would contribute to a variation between calculated and measured values. __________________________________________________ ___________________________________________________ ___________________________________________________ Property of and for the exclusive use of SLU. Reproduction, storing in a retrieval system, distributing, uploading or posting online, or transmitting in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise of any part of this document, without the prior written permission of SLU, is strictly prohibited. 36 EVALUATE REFERENCES: 1. Labvolt Manual 2. Hayt, Jr., W. H., Kemmerly, J. E., & Durbin, S. M. (2010). Engineering Circuit Analysis. New York: McGraw-Hill. 3. Siskind, C. S. (1956). Electrical Circuits. McGraw-Hill.