# Basic question

Discussion in 'Electronic Design' started by Jimbo, Jun 28, 2006.

1. ### JimboGuest

Is there a definition as to what constitutes an "isolated" vs.
"non-isoldated" circuit? What does this really mean? This is what I
think the definition really is:

A system S1 has an input V1,In referenced to V2,In and an output V1,out
referenced to V2,out whereas V1,In - V2,In has an operating limit of L1
and V1,out - V2,out has an operating limit of L2.

Is an isolated system a system that can have the references V2,In and
V2,out such that |V2,In - V2,out| >> 0 and still operate properly? If
so what value of |V2,In - V2,out| constitutes an "isolated system"?

Does anyone know of a formal definition of an "isolated" system? I
know that usually it's some kind of LED operating on some kind of
photo-sensitive device, but is that what the definition is limited to?
I don't think so because a "relay" is usually called an isolated
circuit.

2. ### JimboGuest

opps, sorry for the double post...I tried to correct a spelling error.

3. ### Phil AllisonGuest

"Jimbo"

** "Isolated" usually refers to "galvanic isolation" where no
*electrically conductive* path exists between the devices or circuits
concerned.

There is "transformer isolation", "optical isolation", "relay isolation"
.... etc

Using a coupling capacitor between two circuits produces " DC isolation ".

Like most tech terms, the meaning cannot be defined OUT OF CONTEXT !!

FORGET trying to do that !!!!

** Yawn.....

** A relay provides "galvanic isolation" between the driving and switched
circuits.

........ Phil

4. ### John PopelishGuest

An isolated circuit is one that has a very high resistance to what it
is isolated from. The contacts in a relay are isolated from the coil
wire by the wire insulation, the bobbin the wire is wound on, and the
insulation holding the contacts away from other things. All isolation
has some voltage limit, above which current will take a short cut
around the insulation and surface track or arc.

5. ### JimboGuest

The reason I'm asking is because I have a circuit with two "floating"
inputs but there is a point where the material breaks down. So,
according to your definition this is not "isolated".

6. ### Phil AllisonGuest

** Google Groper Fuckwit Top Poster Alert !!

** Learn to post facts and describe things adequately.

** There ALWAYS is.

That's why all real devices have RATINGS - you bloody FOOL

** You are seriously mentally defective.

GO AWAY !!

........ Phil

7. ### JimboGuest

Thanks for you help Phil.

8. ### GrumpsGuest

So what do you need to know? Do you want a definition of isolation, or an
explanation of why your circuit falls over?

9. ### Guest

Phil, you need some hard man-love to relieve your tension. Come to
Montreal, I'll show you where to go. You might want to come here in the
first week of August. We accept autistic Touretters like you. Bring
condoms.

10. ### LuhanGuest

Shocking!!!!

Luhan

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