lecture note on resistive cicuits by Berihun and Getachew

1. University of Gondar
Institute of Technology
Department of Electrical and Computer Engineering
Introduction to Basic Electric Circuit Analysis Course (ECEG 2121)
Lecture on:
Chapter Two – Resistive Circuits
By: Berihun Kassaw and
Getachew Dereje
2021

2. Circuits with Dependent Sources
Wye Delta Transformations
Series and Parallel Resistor
Combinations
Single-Node Pair Circuit
Single-Loop Circuits
Kirchhoff’s Laws
Ohm’s Law
Learning Objective

3. * Learning Objective
The learning goals for this chapter are that students should be able to:
 Use Ohm’s law to calculate the voltages and currents in electric circuits.
 Apply Kirchhoff’s current law and Kirchhoff’s voltage law to determine the
voltages and currents in an electric circuit.
 Analyze single-loop and single-node-pair circuits to calculate the voltages
and currents in an electric circuit.
 Determine the equivalent resistance of a resistor network where the
resistors are in series and parallel.
 Calculate the voltages and currents in a simple electric circuit using voltage
and current division.
 Transform the basic wye resistor network to a delta resistor network, and
visa versa.
 Analyse electric circuits to determine the voltages and currents in electric
circuits that contain dependent sources.

4. * 1. Ohm’s Law
Ohm – The voltage across a resistance is directly proportional to the
current flowing through it.
Resistor
 a circuit element whose electrical
characteristic is primarily resistive
 are normally carbon composition or
wirewound.
Graphical representation of the voltage–current
relationship for
(a) a linear resistor and
(b) a light bulb.

5. conductance is the reciprocal of resistance
and its unit is siemens.

6. 1. Given the circuits in Figure below, find (a) R and VS in
the circuit a, and (b) find I and R in the circuit b.

7. Definitions of key circuit Terms
A node is simply a point of
connection of two or more circuit
elements
A loop is simply any closed path
through the circuit in which no node
is encountered more than once
A branch is a portion of a circuit
containing only a single element
and the nodes at each end of the
element
The algebraic sum of the
currents entering any node is zero
Kirchhoff’s Current Law (KCL)
The algebraic sum of the
currents leaving a node is zero
the sum of the currents entering a
node is equal to the sum of the currents
leaving the node

8. 1. Find I1 in the networks below. 2. Find Ix, Iy, and Iz in the
networks below.

9. 1. Find Io and I1 in the circuit in
Figure below.
2. Find I1 in the network given
below.

10. Definitions of key circuit Terms
Conservation of energy
Power generation
Power absorption
The algebraic sum of the
voltages around any loop is zero.
Kirchhoff’s Voltage Law (KVL)
The work required to move a unit
charge around any loop is zero

11. 1. Find Vfb and Vec in the circui
below.
2. Find VBE and VDA in the circuit
below.
3. The 10-V source absorbs 2.5 mW
of power. Calculate Vba and the
power absorbed by the dependent
voltage source in circuit below.

12. 1. Find V1, V2, and V3 in the
network given below.
2. If Vx = −12 V in the network
below , find Vs and VBA.

13. Applying Previous Laws
KCL- every node in a single-loop
circuit reveals that the same
current flows through all
elements
KVL
Ohm’s Law (VOLTAGE DIVISION ) ⸫

14. Single-Loop Circuits (Equivalent circuits with multiple
sources )

15. CURRENT DIVISION

16. 1. Find the currents I1 and I2 and the power absorbed by the
40-kΩ resistor in the network below.

17. Equivalent circuits Multiple-Source/Resistor Networks

18. 1. Find the power absorbed by the 6-kΩ resistor in the
network below.

19. Resistance of N resistors in series is
Resistance of N resistors in parallel is

20. Wheatstone bridge circuit is an accurate device for
measuring resistance
When the current in the galvanometer is zero the bridge will be balanced and

21. 1. Find the equivalent resistance at the terminals A-B in the
network below.
2. Find V0

22. 2. Solve the following circuits.

23. 1. Find the equivalent resistance at the terminals shown in the networks
below.

24. 2. Find Vx, Vb, and Vs in the network given below.

26. 1. Find the equivalent resistance RT in the network below.
2. Find Vo and I1 in the network below

27. 1. Find the value of IA
2. Given Io = 2 mA in the network

28. 2. If the power supplied by the 3-A current source in Figure below is 12 W, find VS and the
power supplied by the 10-V source.
1. Find the value of V0 in the figure below

29. 1. Find Vo in the network below
2. Find the power absorbed by the 12-kΩ resistor on the right side of the network in figure below.

30. 1. Use loop analysis to find Vo in the network below
2. Use nodal analysis to find Vo in the network below

31. End of Chapter Two