Question

Norton resistance is found by?

(a) Shorting all voltage sources

(b) Opening all current sources

(c) Shorting all voltage sources and opening all current sources

(d) Opening all voltage sources and shorting all current sources

I had been asked this question in unit test.

My question is from Norton’s Theorem topic in section Network Theorems of Basic Electrical Engineering

Answer 1

Right option is (c) Shorting all voltage sources and opening all current sources

For explanation I would say: Ideal current sources have infinite internal resistance hence behave like an open circuit whereas ideal voltage sources have zero internal resistances hence behave as a short circuit. So, to obtain Norton resistance, all voltage sources are shorted and all current sources are opened.