OrCAD 6.1

[connect21]

A friend of mine just gave me an old copy (1995) of OrCAD 6.1 and I was wondering if anybody had any experience with it. I was wondering if it was esay to use or if I will be spending a lot of time trying to learn a program that is not worth it. I mostly want to use it to simulate some simple circuits.

Thanks

[cato]

I knew Orcad as a schematic capture package. For that it was fairly easy to use, as long as the component you wanted to draw was included in a library. Adding a component to the custom library was a bit of a pain.

However, you seem to be referring to a circuit simulation package. I vaguely remember that Orcad was working on a tie-in with PSPICE, which was (IMHO) a rather clunky simulation package that is praised by those who become fluent in it.

My experiance with Pspice is that if you are inexperianced enough to want to simulate a simple circuit, you are also too inexperianced to use pspice.

If you know enough math, engineering and electronics to use pspice properly, then you probably don't need to use it.

[connect21]

I wanted to make a filter using a capacitor and an inductance and since it is a rather large filter for large current I wanted to simulate it instead of winding different inductance and possibly destroying other components.

Thanks

[MrAl]

Hi there,

There are other programs that are free that are
much newer than that one. For example,
"SwitchCad" is free from Linear Tech.

What is this filter going to be used for?

Take care,
Al

[philba]

Originally posted by cato:
...
My experiance with Pspice is that if you are inexperianced enough to want to simulate a simple circuit, you are also too inexperianced to use pspice.

If you know enough math, engineering and electronics to use pspice properly, then you probably don't need to use it.

I'm sorry but I have to disagree with this. I use switchercad (great program) and when there is an area that I don't understand, I use it in conjunction with textbooks (like, AoE) to get a better understanding. For example, I used it to get a visual of how a low-pass RC filter works. It's a great way to do "lab work" and try lots of different values quickly.

Also, when you have to figure in stuff like ESR and so on, the math gets more complex. The math is easy for me but a lot of hobbiests aren't so fortunate. Using a simulator is perfectly reasonable, especially in light of the alternatives of doing nothing or guessing.

[Joseph]

I really like SwitcherCad, aka, LTspice. It has a GUI which is easier to use than almost all the other ones I have tried. I am not naturally gifted in the area of computers. The best thing about it, too, is it is free. It also has a lot of online group support as well.

[cato]

Originally posted by philba:
I'm sorry but I have to disagree with this. I use switchercad (great program) and when there is an area that I don't understand, I use it in conjunction with textbooks (like, AoE) to get a better understanding. For example, I used it to get a visual of how a low-pass RC filter works. It's a great way to do "lab work" and try lots of different values quickly.

Also, when you have to figure in stuff like ESR and so on, the math gets more complex. The math is easy for me but a lot of hobbiests aren't so fortunate. Using a simulator is perfectly reasonable, especially in light of the alternatives of doing nothing or guessing. [/QB]

I forgive you, even though I said Pspice wasn't user friendly and your response was to say how great switchercad is.

Switchercad is a very limited package aimed at selling switcher chips. Because it is aimed at one thing...LinearTech switcher circuits... it is very user friendly and plug and chuggy.

Pspice is not plug and chuggy. To use it to simulate a switcher..wow...what a nightmare that would be...first you would have to develop a model of the IC....but before you could do that you would have to model the transistors inside the IC....including all their Betas or Hfes temperature coefficients..parasitic capacitances....on and on and on....

Also, this part of your comment:

--The math is easy for me but a lot of hobbiests aren't so fortunate. --

Only serves to support MY point. You understand the math. Therefore, using the simulator is easy for you. If you don't understand the math, using a simulator is confusing. Furthermore, if you don't already know what the answer should be, you have no idea if the answer you get from the simulation is correct or the result is some mistake in the set up of the simulation.

What Connect21 wants to know is, will his circuit work or blow up parts. To know that, you have to simulate all the none ideal aspects of the components, including heat dissipation, temperature coefficients of on resistances, Monte Carlo parameters, worst case parameters...yadda yadda yadda.

If you are a good enough engineer to understand that requirement AND how to correctly simulate all that, you can probably tell if the circuit will work by glancing at the schematic and doing arithmetic in the margin.....

I would also guess that all of that is beyond the capability of switchercad

<small>[ March 05, 2006, 05:46 AM: Message edited by: cato ]</small>

[connect21]

MrAl
I want to make a filter for an inverter that I am trying to make to be used as a welder I am trying to build.
I also found a copy of "Electronics Workbench 4.0" that I used instead of "OrCad" and it works fine but it can do a lot more that what I am able to figure out but there is no tutorial with the software, anybody knows where I can find one. If not I will post again with another title .

<small>[ March 05, 2006, 03:11 PM: Message edited by: connect21 ]</small>

[MrAl]

Hi again connect21,

Oh ok, well if you have a question you can ask
here.
I also use "MicroCap" which is pretty easy to
use...draw your schematic and select the
type of analysis you want (ac, dc, trans, etc).

You have to realize however that when you go to
simulate a circuit like this there are various
things you have to know other than the basic
part values, such as how much series resistance
there is in the inductor, how much ESR in the
capacitors, and sometimes you have to know the
characteristics of the metal itself used for
making the inductor (ie core material).
Because you are dealing with high currents you'll
at least have to know the series R of the
inductor...and that R better be *LOW*
Have to look out for the cap's surge rating too,
or you might end up blowing up some caps (and
that's not pretty as stuff goes flying in all
directions). Wear safety glasses at the very
least.

Im wondering if you have found an inductor yet
or you are winding your own...


Take care,
Al

[Joseph]

I designed this circuit on LTspice. I have used MicroCap and like it too.

<img src="http://img151.imageshack.us/img151/3324 ... 6dp.th.gif" alt=" - " />

Thanks to ImageShack for Free Image Hosting

<small>[ March 05, 2006, 05:09 PM: Message edited by: Joseph ]</small>

[haklesup]

Electronics workbench has a freeware (more like a demo) offer right now for version 9. It's limited in components, layers and is time bombed (sim and autoroute only) but otherwise it is a fully functional powerpro version and you'll be able to save/print the files unlike previous demo versions.

Since their recent acquisition by national instruments, their libraries and simulation tools have improved a bit. (3 versions released in the last year)Look for the DesignSuite Freeware 9 link on their homepage. Get it before they change their mind (even if only for later use).

For what you want to do it shouldn't be too hard but still may take a few hours to figure it out (as it will with any unfamiliar CAD)

[connect21]

If it wasn't for a connection mistake on the power supply, I would have gotten going with Electronics Workbench in a matter of minutes, it is probably the easiest software I have used so far.
I have seen on some demo circuit, that come with the software, that you can trigger some function by pressing some keys on the keyboard, like a macro of something, but I can't find any instruction on how to do that. Also I was wondering if I can add some components and how to do it. There is no tutorial with this software so I am limited.

MrAl

I am planning on winding my own inductor. I have wound a couple so far, I made a large diode bridge that I connected on the output of my Lincoln welder, to have DC current, and I added an inductor, to filter the output a little. I used a large transformer core that I rewound with large wire and added an air gap in the core, of .030" if I remember, so it won't saturate. I was wondering what would happened, in a case like that, if the inductor saturates. When I tested, I started to weld and there was a wrench that stuck to the inductor and I was wondering if that meant anything.

Thanks