sentences:  Then using conventional circuit analysis techniques to express both the voltage across the extra element test source's terminals, , and the current leaving the extra element test source's positive terminals, , and calculating formula_3.Although computation of is an unfamiliar process for many engineers, its expressions are often much simpler than those for because the nulling of the transfer function's output often leads to other voltages/currents in the circuit being zero, which may allow exclusion of certain components from analysis.As a special case, the EET can be used to find the input impedance of a network with the addition of an element designated as "extra".