Norton’s theorem

Norton’s theorem states

‘The current that flows in any branch of a network is the same as that whichwould flow in the branch if it were connected across a source of electrical energy, the short-circuit current of which is equal to the current that would flow in a short-circuit across the branch, and the internal resistance which is of equal to the resistance which appears across the open-circuited branch terminals

* Norton’s theorem is summarized To determine the current flowing in a resistance R of a branch AB of an active network

(i) short-circuit branch AB

(ii) determine the short-circuit current ISC flowing in the branch

(iii) remove all sources of e.m.f. and replace them by their internal resistance or, if a current source exists,replace with an opencircuitthen determine the resistance r,‘looking-in’ at a break made, between A and B

(iv) determine the current I flowing in resistance R from the Norton equivalent network shown in Figure