Circuit drawing software

[JohnW2]

And you can describe it to a simulator including the descriptions of whatever wherever is connected to what as it would be IRL.

I think this discussion is getting rather silly. When eric talked about the software 'not working without an earth', I think what he was trying to say is that it will not (cannot) work unless one tells it ("describes to it") what point in the circuit is to be used as the zero reference point for voltages/pds. The need for that is pretty obvious, and has certainly been true of all such simulation software I've ever come across. Without such instruction about the voltage reference, what is the software meant to do - guess what the referencepoint is, express voltages relative to some randomly chosen point in the circuit or what?

Kind Regards, John

 

[ban-all-sheds]

OK - see my edit which crossed in the post.

Of course you would need to describe to the simulator what voltage points there are, with reference to what other point(s) in the system, but I don't see why that is a "problem".

 

[Monkeh]

This will function IRL with no reference to ground:

Is Eric saying that the simulator he is talking about cannot simulate its behaviour?

'ground' in this context has nothing to do with the big spinning ball under us. It is the 0V reference point.

This is a non-intuitive setup for those who have been educated in electrical installations, not electronic engineering (which involves a great deal of education simply on utilising simulators in a useful manner).

It also has nothing to do with this thread at this point.

 

[JohnW2]

OK - see my edit which crossed in the post. Of course you would need to describe to the simulator what voltage points there are, with reference to what other point(s) in the system, but I don't see why that is a "problem".

I don't see it as a problem, either, and I think eric probably confused things a bit by talking about 'ground', 'earth' or whatever he said - but,as I said, I think he was probably just referring to the (obvious) need for the specification of the "0V" point/line, as in your astable circuit.

Kind Regards, John
Edit: embarrassing typo corrected

 

[ban-all-sheds]

'ground' in this context has nothing to do with the big spinning ball under us. It is the 0V reference point.

Indeed.

So why is it a "quirk" that the simulator won't simulate without you telling it where the reference point is (which could just as well be at the top of the diagram and '-V' shown connected to the emitters) any more than it would be a "quirk" that the system would not oscillate IRL unless you created a potential difference between those two points with a DC supply?

 

[Monkeh]

'ground' in this context has nothing to do with the big spinning ball under us. It is the 0V reference point.

Indeed.

So why is it a "quirk" that the simulator won't simulate without you telling it where the reference point is (which could just as well be at the top of the diagram and '-V' shown connected to the emitters) any more than it would be a "quirk" that the system would not oscillate IRL unless you created a potential difference between those two points with a DC supply?

Because 'ground' is literal to him.

 

[ban-all-sheds]

I don't see it as a problem, either, and I think eric probably confused things a bit by talking about 'ground', 'earth' or whatever he said - but,as I said, I think he was probably just referring to the (obvious) need for the specification of the "0V" point/line, as in your bistable circuit.

Or even an astable one.

"Earth", "ground", "0V" - the terms are irrelevant to the issue, and it was that because to me it seems so blindingly obvious that you'd have to describe that to the simulator that I wondered what I was missing when Eric said "It has some quirks like unless earthed you can't run the program".

 

[JohnW2]

Or even an astable one.

One of these days, I'm going to kill the link between my brain and my typing fingers. Apologies - I'll correct it, lest any readers get confused

"Earth", "ground", "0V" - the terms are irrelevant to the issue, and it was that because to me it seems so blindingly obvious that you'd have to describe that to the simulator that I wondered what I was missing when Eric said "It has some quirks like unless earthed you can't run the program".

I agree. Unless he really was talking about some bizarre software (which describes its voltage reference point as 'earth' or 'ground'), I think his choice of words was probably somewhat sub-optimal!

Kind Regards, John

 

[ban-all-sheds]

If I'm understanding him correctly, he's complaining that you must have a ground (or earth..) point in the simulation and cannot have any floating sections of circuit, or the simulator will not run.

Floating wrt what?

Ground?

A nominal 0V point?

If he really does mean ground, and as we all know there are uncountable examples of systems which work just fine with no reference to ground, then I put it to you that that's more than a "quirk", it's a tool which is not fit for purpose.

If he means a nominal 0V point then again we come back to the principle that if the system will work, somehow, IRL, with parts of it floating wrt that 0V point then so should the simulation.

You can build something which works well, or is flaky, or doesn't work at all. But however it performs the simulator must be able to accurately simulate it or it is not a simulator.

 

[ban-all-sheds]

One of these days, I'm going to kill the link between my brain and my typing fingers.

No need - it appears to already be dead.

(Or floating.)

 

[Monkeh]

Unless he really was talking about some bizarre software (which describes its voltage reference point as 'earth' or 'ground')

Most simulators refer to the reference as 'ground', as that is standard electronic nomenclature..

If I'm understanding him correctly, he's complaining that you must have a ground (or earth..) point in the simulation and cannot have any floating sections of circuit, or the simulator will not run.

Floating wrt what?

Ground?

A nominal 0V point?

These are one and the same thing in this context.

I see eric is not the only one stumbling on this point.

 

[ban-all-sheds]

Most simulators refer to the reference as 'ground', as that is standard electronic nomenclature..

Fair enough.

So in what way can it be a "quirk" to have to tell the simulator where the reference point is?

I see eric is not the only one stumbling on this point.

I'm not stumbling over the point of having to specify where the reference point is, and any other points with a PD wrt that point.

I am, and have always and only been "stumbling" over "It has some quirks like unless earthed you can't run the program".

I cannot for the life of me see how that's a quirk, no matter how you interpret "earthed".

 

[Monkeh]

It's only a quirk if you interpret the term 'ground' as a connection to the Earth. If you can see no other definition, then it seems very odd that everything must have a point connected electrically to the planet.

 

[JohnW2]

Most simulators refer to the reference as 'ground', as that is standard electronic nomenclature..

I'm not so sure about that as a generalisation. Particularly in terms of RF circuitry, 'ground' and the reference point for the DC supply to the circuitry are not necessarily the same thing.

Kind Regards, John

 

[JohnW2]

I cannot for the life of me see how that's a quirk, no matter how you interpret "earthed".

I think that both Monkeh and I have already essentially agreed with you. You really don't need to keep repeating your point - which, as so very often, is essentially about semantics.

Kind Regards, John