Electrical Engineering Question

Murray State University School of Engineering EMT 110: Electrical Circuits I – Exam #1 Review Units, Measurements, and Linear Circuit Analysis Instructor: Tyler D. Stoffel Spring 2024 Tuesday, February 27 Name: This exam contains 15 pages (including this cover page) and 13 questions. Total of points is 100. Instructions Solve each problem and circle or box your final answer with the correct units (if applicable). Be sure to show your work for partial credit where applicable. You may use a calculator as well as one 8.5 × 11” sheet of paper (front and back) with equations, diagrams, etc. Please turn in your sheet with your exam. Supplemental materials are printed at the end of the exam. Distribution of Points Question: 1 2 3 4 5 6 7 Points: 10 6 6 6 5 5 9 Question: 8 9 10 11 12 13 Total Points: 6 10 8 9 10 10 100 Score: Score: 1 EMT 110: Electrical Circuits I Exam #1 Review 1. (10 points) Express the following using metrix prefixes. (a) 0.0316 A (b) 33 100 V (c) 0.000 073 1 Ω (d) 926 000 000 W (e) 5.76 × 106 Ω 2. (6 points) Perform the following operations. (a) 150 mV ÷ 25 µV (b) 20 kΩ ÷ (1.10 kΩ + 10 kΩ) (c) 1 MW ÷ 5 kW Page 2 of 15 Spring 2024 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 3. (6 points) State the color bands for each of the following resistance values and tolerances. (a) 10 kΩ ± 5% (b) 2.70 MΩ ± 10% (c) 7500 ± 375 Ω Re d Bla c Bro k wn Sil ver 4. (6 points) State the resistance values and tolerances (%) for each of the resistors. ld Go Bro Bla wn ck Blu e (a) Vio Gr let ee Or n ang e Go ld (b) (c) Page 3 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 5. (5 points) A resistor has 5.50 V across it and 3 mA through it. What is the power dissipation? 6. (5 points) A flashlight is operated at 3.20 V and has a resistance of 3.90 Ω when the filament is hot. What current is provided by the batteries? Page 4 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 7. A circuit is steadily operated with 6 light bulbs in parallel which are rated at 90 W each. The supply voltage (Vs ) is 24 V. Determine the following: (a) (5 points) The current Ieach through each bulb. (b) (4 points) The total energy Etot dissipated in kW h if the circuit is operated for 12 hours. Page 5 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 8. A small loaded circuit with internal resistances R1 , R2 and supply voltage Vs is shown in Figure 1. R1 750 Ω R2 Vs + 24 V − 5.50 kΩ RL Figure 1: A loaded circuit. Determine the following: (a) (4 points) The load resistance RL which will maximize the power delivered to the load. (b) (2 points) The power PL delivered to the load using the value of RL you determined. Page 6 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 9. (10 points) A series/parallel resistor circuit is shown in Figure 2. R1 R3 A 9 kΩ Vs + − 11 V 1.50 kΩ 5.50 kΩ R2 3.50 kΩ R4 B Figure 2: A series/parallel circuit. Determine the Thevenin resistance RT H and voltage VT H as seen from point A to point B. Page 7 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 10. (8 points) A Wheatstone Bridge circuit is shown in Figure 3. R 2 3. 20 kΩ 0Ω 23 R1 Vs + − 5V Vout R 3 70 2. kΩ R4 Figure 3: Wheatstone bridge circuit. Determine the resistance R3 required to balance the bridge so that Vout = 0. Page 8 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 11. A series/parallel resistor circuit is shown in Figure 4. R2 = 1 kΩ + R4 = 3 kΩ R3 = 2 kΩ R5 = 5 kΩ R1 = 10 kΩ R6 = 5 kΩ – Figure 4: Series/parallel resistor circuit. Determine the following: (a) (6 points) The total equivalent resistance RT . (b) (3 points) The current I2 through R2 if the supply voltage is Vs = 12 V. Page 9 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 This page is intentionally left blank to accommodate work that wouldn’t fit elsewhere and/or scratch work. Page 10 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 12. (10 points) A circuit with multiple voltage sources is shown in Figure 5. R1 R3 1.50 kΩ 2.50 kΩ R2 2.00 kΩ 1.00 kΩ R4 V1 + − 12 V 10 V + − V2 8V + − V3 Figure 5: A circuit with multiple voltage sources. Determine the current through the resistor R3 using Superimposition Theorem. Page 11 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 This page is intentionally left blank to accommodate work that wouldn’t fit elsewhere and/or scratch work. Page 12 of 15 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 13. A voltage divider with a DMM (digital multimeter) measuring across one of the resistors is shown in Figure 6. 1 MΩ R1 5 MΩ R2 Vs + − 12 V 10 MΩ Rm Figure 6: A loaded voltage divider. You are trying to measure the voltage V2 across the resistor R2 using the DMM, but you’re concerned that the DMM’s resistance may be affecting your measurement. Determine the following: (a) (5 points) The voltage across the resistor R2 for the circuit assuming the voltage divider is stiff. In other words, the voltage V2,stiff if the DMM’s resistance Rm is not present in the circuit. (b) (5 points) The actual voltage across the resistor R2 for the circuit (assuming the voltage divider is not stiff). In other words, the voltage V2,actual if the DMM’s resistance Rm is present in the circuit. Page 13 of 15 EMT 110: Electrical Circuits I Exam #1 Review Supplemental material Figure 7: Color code chart for four band resistors. Page 14 of 15 Spring 2024 EMT 110: Electrical Circuits I Exam #1 Review Spring 2024 This page is intentionally left blank to accommodate work that wouldn’t fit elsewhere and/or scratch work. Page 15 of 15