1. Sep 2, 2011

### djrama

Hello!!

My version of OrCAD (16.0) doesn't have a pspice model for the 7824 regulator... I was searching in google for information but I haven't found anything useful.

Maybe modifying 7815 model (which I already have) or something, but I don't know how to do this.

Any help would be appreciated!

Thanks.
Daniel.

2. Sep 2, 2011

### Staff: Mentor

Welcome to the PF.

I think those are just jellybean linear regulators, so the difference is just the output voltage setting, right? You should be able to figure out where the voltage divider/setting circuit is in the 7815 regulator model, and just change the divider to give you 24V.

3. Sep 2, 2011

### yungman

May I make a suggestion?

Why even do any pspice on a common voltage regulator? Do it on circuit you design!!!!

I have to say, don't get too depend on any simulation program. I take that you are a student, learn to look at the circuit diagram of 7824/78xx and learn how it work. You don't get insight using pspice at all. I can tell you in my 30 years of career doing heavy duty analog circuit design, I never use any simulation program until RF. I only use Microwave Office because of the complexity of the circuit model with all the parasitic components and also at the speed that speed of light become an issue and signals has to be represented as phasors and travelling waves. Also the Smith Chart is not exactly intuitive. In fact Microwave Office help me start thinking in Smith Chart, how the circuits dancing on the Smith Chart!!!!:rofl:

It is like with all the GPS and cell phone with memory and intelligence, I still try to remember phone number and remember the direction and look up maps. One day if there's an EMP pulse, people will be totally loss!!!

If you want to learn pspice, design an op-amp ( transistor level) then do the simulation. Or start out with a single stage transistor and to differential pair, then current mirror and then add them together. Verify Bode Plot along the way. Don't think those circuits are that complicated. Learn to break them apart into building blocks and it is very easy to understand.

Just a thought

Last edited: Sep 3, 2011
4. Sep 3, 2011

### djrama

Absolutelly right, and yes, in my previous university courses I have learn about calculations in several electronics circuits (maths, maths, maths...) but in this case, the problems cames by the teacher who wants to have the pspice simulation of the whole project, not only the 7824.