if i just measure the resistance btw L and N , the resistance should be zero right, then how can it be 0.3 ohms ?
What information are you given about the source impedance for the AC Mains feed of Line and Neutral into this circuit? The source impedance is in parallel with the circuit impedance. Is this for schoolwork? If so, I will move your posts to the Homework Help forums.
im using the software for Troubleshooting Electrical circuits by BNN. studying this to get prepared as electrician. for if you look at the last 2 pictures, you can see that you can still get 0.3 ohms if the black wire is unplugged
I guess by zero resistance you mean infinite resistance. And does the circuit work as it should (all switches on - bulb shines, at least one off - bulb off). I hope, you measure it when you have the circuit disconnected from power source. And by the way, you measure on real circuit or are we still talking about that SW?