1. Electromagnetism Lecture#10 MUHAMMAD MATEEN YAQOOB THE UNIVERSITY OF LAHORE SARGODHA CAMPUS

2. KIRCHHOFF'S VOLTAGE LAW The sum of all the voltage drops around a single closed path in a circuit is equal to the total source voltage in that loop. Vs = V 1 + V 2 + V 3 +... + Vn MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

3. VOLTAGE SOURCES IN SERIES Recall that a voltage source is an energy source that provides a constant voltage to a load. Batteries and electronic power supplies are practical examples of dc voltage sources. When two or more voltage sources are in series, the total voltage is equal to the algebraic sum of the individual source voltages. V S(tot) = V S1 + V S2 +... + V Sn MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

4. VOLTAGE SOURCES IN SERIES MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

5. VOLTAGE DIVIDERS A circuit consisting of a series string of resistors connected to a voltage source acts as a voltage divider. Two-resistor voltage divider. MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

6. Voltage-Divider Formula Vx = (Rx/Rt)Vs The voltage drop across any resistor or combination of resistors in a series circuit is equal to the ratio of that resistance value to the total resistance, multiplied by the source voltage. MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

7. POWER IN SERIES CIRCUITS The total amount of power in a series resistive circuit is equal to the sum of the powers in each resistor in series. P T = P 1 + P 2 + P 3 +... + P n The following formulas are used to calculate the total power: MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

8. Problems related to Kirchhoff's Voltage Law Q.1Five resistors are in series with a 20 V source. The voltage drops across four of the resistors are 1.5 V, 5.5 V, 3 V, and 6 V. How much voltage is dropped across the fifth resistor? 4 V MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

9. Q.2Determine the unspecified voltage drop(s) in the circuit of following Figure. Show how to connect a voltmeter to measure each unknown voltage drop. 6.8 V MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

10. Problems related to Voltage Dividers Q.1The total resistance of a circuit is 560Ω. What percentage of the total voltage appears across a 27 Ω resistor that makes up part of the total series resistance? 4.82% MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE

11. Q.2Determine the voltage with respect to ground for output A, B, and C in the following Figure. RT=18.9KΩ, VA=15 V, VB= 10.6V, VC= 2.62V MATEEN YAQOOB DEPARTMENT OF COMPUTER SCIENCE