Neon bulb application...Ist it possible.....?

[pranam77]

**broken link removed**
On this page there are some Neon bulb application circuits to check AC. But i found no details about what i expect. In fact i need to have two wires with neon or any other bulb and i need to glow it only when i touch it to AC Phase and neutral. The bulb shouldnt glow if i connect to the Phase and earth. Is this possible?..

 

[FvM]

The bulb shouldnt glow if i connect to the Phase and earth. Is this possible?..

It can't be distinguished in any wiring system with neutral connected to earth.

 

[abhijithvp]

It can't be distinguished in any wiring system with neutral connected to earth.

by the way, is there any practical application for this circuit, if made possible?

 

[FvM]

I guess, the intention is to detect a reversal of protective earth and neutral wire.

 

[pranam77]

Yes..in some connections where Proper "earth" is not available, i have seen the body connected to "neutral" which is bvery dangerous. In this case, the circuit is very useful for detecting wether a proper earth is given or the body is connected to the negetive. Even it may be used to check wether AC volatge is available if the bulb glows only in case the two leads are connected to Phase and neutral only.

 

[abhijithvp]

oh..got the point.
but, if 'body connected to neutral is the situation', then isn't it enuf to check continuity?

or..i think it'd be bettr use the fact that neutral always has some potential greater than earth. design a simple ZCD or high gain amplifier and in its output, connect a bulb. if bulb glows, den possibly neutral or any disturbed earth is connectd. ???