virtual earth

[daiplayer]

Any body got some input on this?

Was talking to a guy that said he used this in domestic fault finding earth faults.
He ( where i would normally take an hr or so ) managed to locate and isolate a ring fault in ten mins. .

Any ideas?

 

[Engineer54]

Used what?? Think you need to give us a bit more detail than that!!!

 

[kingeri]

Don't honestly know what you mean!

 

[Marnik]

Sounds like (virtual) guesswork to me,does he issue virtual certificates etc.?

 

[Swicade]

The only virtual earth i know of exists in a virtual world where every sparks living there can only earn thier 'Qaulified' status after 3 or more years of onsite experience along with technical training.....

:wheelchair:

 

[daiplayer]

Clues in the title . ..........
Found this :-
The virtual ground concept aids circuit analysis in operational amplifier and other circuits and provides useful practical circuit effects that would be difficult to achieve in other ways. An ideal virtual ground would be able to source/sink an infinite amount of current. In practice, the sourcing/sinking capability is determined by the other circuit impedances and the amplifier used.

How to create a virtual ground point:
Since an operational amplifier has very high open loop gain, in negative feedback circuits the amplifier acts automatically to make the potential difference between its inputs tend to zero. Consider the simple inverting configuration below. If the non-inverting (+) input of the operational amplifier is grounded, then its inverting (-) input, although not connected to ground, will assume a similar potential, becoming a virtual ground.

 

[daiplayer]

Cant read a title?

 

[kingeri]

Cant read a title?

Is that an attempt at being rude?

 

[kingeri]

It does sound interesting, though upto now I've never given it a thought. I tend to be more conventional!

 

[daiplayer]

It does sound interesting, though upto now I've never given it a thought. I tend to be more conventional!

me too , but it amazed me how he did something or other, did a few tests ( loop testing i think ) , and found the fault in literally under ten minutes . i wanna know how he did it ! lol

 

[kingeri]

me too , but it amazed me how he did something or other, did a few tests ( loop testing i think ) , and found the fault in literally under ten minutes . i wanna know how he did it ! lol

It sounds like it could have potential, if saving time is important to you. Sometimes it can be good if a job takes a while though, especially when you don't have any more lined up!

 

[Geordie Spark]

me too , but it amazed me how he did something or other, did a few tests ( loop testing i think ) , and found the fault in literally under ten minutes . i wanna know how he did it ! lol

Did you ask him to explain it to you?

 

[daiplayer]

he's gone away working now , he said he would show me when he got back .

 

[StuSpiers]

You can quite easily locate a break in a ringmain doing nothing but Zs readings.

Don't need any gizzmos either.

 

[Geordie Spark]

he's gone away working now , he said he would show me when he got back .

Well when he does, maybe you can start another thread and tell us all about it?

 

[Knobhead]

Clues in the title . ..........

How to create a virtual ground point:
Since an operational amplifier has very high open loop gain, in negative feedback circuits the amplifier acts automatically to make the potential difference between its inputs tend to zero. Consider the simple inverting configuration below. If the non-inverting (+) input of the operational amplifier is grounded, then its inverting (-) input, although not connected to ground, will assume a similar potential, becoming a virtual ground.

So it's not this then?
View attachment 14719
Sorry to say I slept through OpAmps at collage. Not that it mattered, other than collage I've not tested one for fourty years.

 

[daiplayer]

ha ha ha !!! what a tt !! lol

 

[boberty]

Did he use the circuit tester that IDEAL make think its called a sure tester. Which will put a signal on to the circuit being tested, then you can trace it with a hand held meter. When it gets to the cause of the fault it gives a signal. Seem to remember them being £420 or pay a bit extra and you can also use as a cat scanner the gas and water use for underground services.

 

[daiplayer]

I really aint sure mate. He did the fault , then walked out ( seemed in a rush )