normally the three wires are active - or at least active at some time. The neutral would be wired separately from the switches. (note with Australian switches there is a free terminal that can be used to join wires). As for the wiring diagram - there is 4 possible combinations for the switches. Copy the diagram 4 times and mark with a red pencil the switch path. Follow the path in each of the 4 instances and note what happens. I can tell you both switches on and both off result in the light being off.

You should include wiring diagrams. There are many ways to wire 3-way switches (That's what we call them here in Canada). How many switch boxes are there, how many wires are in each box and how are they grouped, eg 2 boxes, one has a 2 wire(+G), a 3 wire and another 2 wire and the other has just a 3 wire in it, or each box has a 2 wire and a 3 wire. What is the wiring method? NMD90? Pipe?

The 3 wire cable that goes between the two 3 way locations will be either 2 switch legs and a neutral or 2 switch legs and a return switch leg in the examples I gave above.

The "Standard wiring" in the first example you link to is garbage. The Second example they give is one of the standard wiring arrangements.

@KH, the switch is exactly the same in the link in my post, in my notation, wire 1 at the top, wire 2 in the middle and wire 3 at the bottom. The wiring diagram is what i wish to know given my testing. thanks

Light switch does not have neutral. One wire is phase, second to load.

Your testing is inadequate and you need to answer the questions I asked for us to help you. The picture you've now included in the question is the one from the article that is nonsense. It won't work. Power has to go into the common of one switch, the other two contacts are attached to 2 "traveller" wires that go to either a 4-way switch or the 3 way switch that ends the run. Your switch leg comes out from the common of that other 3 way switch. From there it either goes out to a device directly, in which case the 3rd wire that comes with the travellers is used as a neutral,

or if there are only 3 wires total in the box, that means that the load is back at the first switch so the third wire is used as a return switch leg and there is no neutral. To be clear it does not just matter how many wires attach to the switch, you need to know how many wires are in the box to figure out what is going on.

@KH - it will work. It isn't nonsense. But anyway - this question should be migrated to another site (home improvement?).

Are you sure you didn't mistake line for ground? It would explain the weird results with your test screwdriver.

@Andyaka Hmm right you are. On the other hand it seems needlessly convoluted. Ok so I retract my statements about it not being viable, but it would still be best to give us the full wiring arrangement in the box (preferably both switch boxes). The article is also claiming the convoluted arrangement is new, but some of their quoted reasons don't seem right to me like that what they refer to as the old method causes wiring loops where return currents are in cables far from line currents.

@KH that picture was not added by me (someone edited it), if this picture is correct, 2 of the wires should be tested "live", but only one in my test unfortunately. That's why I wish to know what is the wiring inside in my light. thanks

@DayDayHappy Ok I'm going to try to be more clear about this. For there to be one 3 way switch, there must be a second 3 way switch. What I want you to do is power down the circuit and open up both 3 way switch boxes. Take a clear picture of the wires inside. If you disconnect the switches, note which wire goes to which contact beforehand. See Tony's Answer. There are multiple ways the switches could be wired. Edit your question and add the pictures and then we can figure out which way it is wired.

Which country are you in? US, UK, somewhere else? Wiring standards and even the name we call this circuit changes from country to country so we need to know where you are to give an appropriate answer.

@GrahamNye One clear advantage of the "old way" I see is that 4-way switches can be added in the middle to switch at 3 or more points. Perhaps Tony could find a way to chain 4 ways into the other wiring arrangements and make it work, but it looks like a nightmare to my eyes. One clear advantage of the "new way" I see is that it passes the Line wire, so you could actually reasonably run 4 wire (R,Bk,Bl,W) instead of 3 wire to pass a neutral and get further use of the circuit from the far end without backtracking. Do you have 4 way switches? I suppose you would call them 3 way.

@KH "it seems needlessly convoluted" It is correct and is the standard way of wiring what we call a 2-way switch in the UK. (It is drawn somewhat oddly though.) The quoted reasons for avoiding the older wiring method are off the mark. The actual reason is that the older method requires the switched feed returning from the far switch to be jointed in the back of the switch with the cable running to the light. In UK writing practice we try to avoid joints in the back of wiring boxes. The preferred circuit allows all connections to be made on the back of the light switch itself.

@GrahamNye Very interesting. I use screw terminals when possible by preference because of the minimal damage to the wire, but I can't imagine electricians having much insecurity about tucking back a properly done splice and if you were really concerned about long term damage to the wires from repeated twisting you could use Wagos. I suppose you'd have lower box fill in general, but I tend to favor slightly oversized boxes anyway. I'm definitely going to remember this in case it helps me make fill on a box I don't want to cut out some day.

@KH 4-way switches are known as intermediate switches in the UK. You can use them with the new wiring. L1 and L2 connect to the switch and the COM traveller is jointed in the box. Typically you can use 3 phase+earth cable. The link shows the old colours (red, yellow, blue) but newer cable will use brown, black, grey. The feed cables also show old colours of brown(live) and black (NEUTRAL) but the drop cable to the bulb holder uses the new colours of brown(live) and blue(neutral).

@KH We don't use wire nuts so no twisting. We use screw blocks (pictured in the previous link) or wago terminals.

@GrahamNye I just looked up your color codes and discovered many other countries' color codes make me uncomfortable. Horrifying. I really like RBB and OBY and white neutrals are nice too.