124 lechniques0fti,cuitAnatysis If the circuit or network contains dependent sources, an alternative procedure for finding the Th6venin resistance Rrr is as follows. We fi$t deactivate all independent souces, and we then apply either a test voltage source oi a test culrent source to the Th6venin terminals a,b. The Th6venin resistance equals tle ratio of the voltage acmss the test source to t}Ie cur-rent delivered by the test source. Example 4.11 illustrates this alternative procedure for fhding Rrh, using the same ciicuit as Example 4.10. Finding the ThEvenin Equivalent Using a Test Source Find the Thdvenin resistance Rrh for the circuit in Fig.4.49, using the alternative method descdbed. 5olution We filst deactivate the independent voltage source ftom t}Ie circuit and then excite the circuit ftom the teminals a,b with either a test voltage souice or a test current soruc€. If we apply a test voltage source, we will know t}Ie voltage of the dependent voltage source ard hence the controlling curlent i. Therefoie
This is the end of the preview.
access the rest of the document.
Ratio, 2000, Electrical resistance, test voltage, fhding Rrh