experiment 4 thevenin and norton equivalent circuits, Summaries of Electronics

Download experiment 4 thevenin and norton equivalent circuits and more Summaries Electronics in PDF only on Docsity! EXPERIMENT 4 THEVENIN AND NORTON EQUIVALENT CIRCUITS The objective of this experiment is to study Thevenin's and Norton's theorems and their application in circuit analysis. OBJECT 1. Function/Arbitrary Waveform Generator (AATech AWG 1020A) EQUIPMENT LIST 2. Multimeters 3. Breadboard 4. Resistors: 1.2 kΩ, 1.8 kΩ, 2.7 kΩ, 4.7 kΩ, 5.6 kΩ, 2x10 kΩ 5. Potentiometer: 10 kΩ 1. Research the intended purpose of Thevenin’s and Norton’s theorems. PRELIMINARY WORK 2. Research how Thevenin voltage and Norton current can be determined in a circuit. 3. Construct the Figure 4.1 on PSpice program. Follow the experiment steps (from 1 to 10) on PSpice and note the observed results to your pre-lab report which will be submitted. THEORY Thevenin’s Theorem Thevenin’s Theorem is a very powerful tool for simplifying a linear two-terminal network of fixed resistances and voltage sources by replacing the network with a single voltage source in series with single resistor. When the circuit is simplified, the single voltage source is called the Thevenin voltage source (providing Thevenin voltage (VT)) and VT is equal to the open circuit voltage (VOC) at the terminals (a-b) of the original network. The single resistor is called the Thevenin resistance (RTH) and is equal to the open circuit voltage (VOC) at the terminals divided by the short circuit current (ISC) between the terminals of the original network. Therefore, VTH = VOC and RTH=VOC/ISC The short circuit current (ISC) is measured by connecting an ampermeter between the terminals (a-b) of the original network and recording the current reading. The short circuit Adnan Menderes University Elec. & Electronics Eng. Dept. EE209 Circuit Laboratory I 2015-2016 current (ISC) is calculated by drawing a short between the terminals of the original network and calculating the current in the short. An alternate method of determining the Thevenin resistance (RTH) is by replacing all voltage sources with a short circuit and all current sources with an open in the original network and determining the equivalent resistance is equal to the Thevenin resistance (RTH). The strength of the Thevenin theorem lies in the fact that, although the Thevenin equivalent circuit is not the original circuit, it acts like the original circuit in terms of the voltage and current at the terminals. a Norton’s Theorem Norton’s Theorem states that any linear two-terminal network of fixed resistances and voltage sources may be replaced with a single current source in parallel with a single resistor. The single current source is called the Norton current source (providing Norton current (IN)) and IN is equal to the short circuit current (ISC) between the terminals of the original network. The single resistor is called the Norton resistance (RN) and is equal to the Thevenin resistance in the Thevenin equivalent circuit. It is found by following the same procedure that was used to find Thevenin resistance (RTH). When a resistance RLoad is connected between the terminals a-b of the original network, the voltage across the terminals (VAB) will be the same as the voltage across the terminals of the Thevenin equivalent circuit if the same value resistance (RLoad) is connected across the terminals of Thevenin equivalent circuit. The same statement can be made for the Norton equivalent circuit. 1. Set up the circuit in Fig. 4.1: PROCEDURE Figure 4.1. Linear Circuit to Study Thevenin and Norton 2. Measure the current (IL ), through RLoad and the voltage (VL ), across RLoad. R1 = 1.2 k Ω R2 = 10 k Ω R3 = 5.6 k Ω R4 = 10 k Ω R5 = 2.7 k Ω R6= 4.7 k Ω Rload = 1.8 k Ω VS1 =10 V VS2 = 6V