EMT 1143 INTRODUCTION TO ELECTRIC CIRCUITS CHAPTER 3

EMT 114/3 INTRODUCTION TO ELECTRIC CIRCUITS CHAPTER 3: Circuit Analysis Method 3. 3 Source Transformation School of Microelectronic Engineering, Universiti Malaysia

CH 3: CIRCUITS ANALYSIS METHOD q Node Voltage q Mesh Current q Source Transformation ØThevenin ØNorton ØPower School of Microelectronic Engineering, Universiti Malaysia

Source Transformation - Source transformation is another tool for simplifying circuits. - Basic to this tool is the concept of equivalence A source transformation is the process of replacing a voltage source Vs in series with a resistor R by a current source Is in parallel with a resistor R or vice versa School of Microelectronic Engineering, Universiti Malaysia

Recall Types of sources School of Microelectronic Engineering, Universiti Malaysia

Source Transformation School of Microelectronic Engineering, Universiti Malaysia

Example School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

CH 3: CIRCUITS ANALYSIS METHOD q Node Voltage q Mesh Current q Source Transformation ØThevenin’s Theorem ØNorton ØPower School of Microelectronic Engineering, Universiti Malaysia

Thevenin’s Theorem Thevenin’s theorem states that a linear two-terminal circuit can be replaced by an equivalent circuit consisting of a voltage source VTh in series with a resistor RTh, where VTh is the open-circuit voltages at the terminals and RTh is the input or equivalent resistance at the terminals when the independent sources are turned off. Thevenin’s theorem is very important in circuit analysis. It helps to simplify a circuit. A large circuit mat be replaced by a single independent voltage source and a single resistor. School of Microelectronic Engineering, Universiti Malaysia

Replacing a linear twoterminal circuit by its thevenin equivalent: (a) original circuit, (b) the Thevenin equivalent circuit School of Microelectronic Engineering, Universiti Malaysia

Thevenin Equivalent Circuit Thevenin equivalent circuit consist of an independent Voltage Source, VTH in series with a Resistor RTH. The major concern right now is how to find the Thevenin equivalent voltage VTH and resistance RTH to form an equivalent circuit. School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

Example 1: Find the Thevenin equivalent circuit of the circuit below at terminal a-b School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

Show them another method to find RTh by turning of all the sources School of Microelectronic Engineering, Universiti Malaysia

CH 3: CIRCUITS ANALYSIS METHOD q Node Voltage q Mesh Current q Source Transformation ØThevenin ØNorton ØPower School of Microelectronic Engineering, Universiti Malaysia

Norton’s Theorem states that a linear two terminal circuit can be replaced by an equivalent circuit consisting of a current source IN in parallel with a resistor RN : where IN is the short-circuit current through the terminals and RN is the input or equivalent resistance at the terminals when the independent sources are turn off. School of Microelectronic Engineering, Universiti Malaysia

Norton Equivalent Circuit (a) Original circuit, (b) Norton equivalent circuit School of Microelectronic Engineering, Universiti Malaysia

Example 2: Find the Norton equivalent circuit of the circuit below at terminal a-b School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

Step 4: Source Transformation producing the Norton equivalent circuit School of Microelectronic Engineering, Universiti Malaysia

CH 3: CIRCUITS ANALYSIS METHOD q Node Voltage q Mesh Current q Source Transformation ØThevenin ØNorton ØPower School of Microelectronic Engineering, Universiti Malaysia

Maximum Power Transfer School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

Example School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

Refer textbook: pg 150 School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

School of Microelectronic Engineering, Universiti Malaysia

Ilmu Keikhlasan Kecemerlangan School of Microelectronic Engineering, Universiti Malaysia