Thevenin’s Theorem La Report,
Calculator RTH as follows RTH = VTH/ ISC Method 2: (By measuring the equivalent resistance) Remove all sources from the circuit, i. e. replace all voltage sources with a short-circuit and current sources with an open-circuit. Then with the help of a multimeter find the resistance between the points ‘a’ and ‘b’, denoted by Req. RTH = Req Method 3: (By applying known voltage and measuring source current). We can also find RTH by applying a known voltage to the circuit between points ‘a’ and ‘b’, then measuring the current from the voltage source.
Suppose 1 Vdc is applied as the test voltage then, RTH = Vtest / I 4. Method 4: (By inserting two different resistors and measuring current) There is another method to find the value of RTH, by inserting two different loads between points ‘a’ and ‘b’ i. e. insert resistors R1 and then R2 one by one and write expression for the current through that particular resistor as given below, Current through the resistor R1 :- I1 = VTH / (RTH + R1) Current through the resistor R1 :- I2 = VTH / (RTH + R2) Simultaneously solving these equations will give the value of RTH.
Procedure: We connected the circuit on breadboard as shown in the fig below. Our aim was to determine the current through and the voltage across the 1k? resistance R1 connected between the two nodes A and B. We followed the following procedure to validate the Thevenin’s theorem. Finding VTH: 1. We removed the resistor R1 from the circuit on breadboard. 2. We then determined the open-circuit voltage (voltage between points A and B i. e. VAB) using a voltmeter. This is the required Thevenin voltage VTH. We recorded this value in Table. Finding RTH: 1.
We determined RTH by method A. Further connected an ammeter between load points A and B to measure the short-circuit current ISC. Found the value by RTH = VTH / ISC 2. We then determined RTH by method B. Replaced the voltage sources with short-circuits. Then using an ohmmeter, we found the equivalent resistance between load points A and B. This is RTH. 3. We also determine RTH by method C by Applying a known DC voltage (1 V) between points A and B. Then using an ammeter, we found the current through the test voltage source. We found RTH by: RTH = Vtest / I 4.