61 Norton Theorem Step 1 Find the Norton resistance, RN by removing the 4Ω resistor and replace the voltage source with a short circuit. Figure 3.1(b) Figure 3.1(c) RN = (2//3) + (5//6 = (2)(3) + (5)(6) = 3.927 Ω (2 + 3) (5 + 6)