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# Palmtop Circuit

**Contents of this page**

## Introduction

Palmtop Circuit is a wonderful piece of software, made by the Hungarian company Design Soft, which allows a DOS PC user to draw and analyze electronic circuits. It also runs fine on the HPLX DOS palmtops, and it is even developed especially for these nice machines. Hence the name "Palmtop Circuit".

The following is an article I wrote about Palmtop Circuit (PaCi) to the HPLX mailing list in 1999:

As some of you know, I bought Palmtop Circuit from Design Soft a few months ago. Maybe you remember the problems Tamas Feher had with Design Soft when he tried to convince them to sell PaCi to us. But he did it - and I'm very thankful for that.Design Soft sold it only because of a promise that they got abt. 10 orders (I didn't remember the exact number). I don't know if they got all these orders, but I doubt it, because noone is reporting or asking about it on this list.

So I now want to let you know my experiences with Palmtop Circuit. Maybe this helps some of you to decide if you want to buy it or not.

First of all let me say, i never used PSpice or another circuit analysis program, so I'm not able to compare PaCi with one of these products.

And: I have no relation to Design Soft, so I have no interest in advertising PaCi. The reason for that I'm writing this report is, that I remember the long discussions with Tamas Feher who contacted Design Soft to convince them to sell PaCi to us.

I want to thank Tamas for his efforts, because I now find that PaCi is a really great piece of software!

About PaCi:

PaCi is a software package (installed size about 800k-1M, depending on installation of sample files etc., cost 80 US$, if I remeber correctly, but for exact price please ask Tamas Feher, he is also a list member) that lets you design AND analyze electronic circuits with a high complexity. The manual says 'more than 100 nodes, depending on amount of RAM' - I didn't reach the limit by now... ;-).

It's able to do DC, AC and transient analysis of linear and non-linear electronic networks. The look of the drawn circuits is not as good as probably of the newer PSpice products, but it does its job very well.

The manual of PaCi is _extremly_ good - a short introduction, then follows an exercise by means of an example RLC-circuit, and after that, all the menu items (there are much!) are described. What's also worth to be mentioned is that the principles of the program are also described in the manual. You can read there about Laplace transformation, Fourier transformation, Fibonacci' search method, Gaussian elimination method for solving equation systems and much more.

Now I'll tell a little bit about the work with PaCi:

After you started PaCi, you see a screen that is similar to a drawing software. A grid, a menu and a status line. If you press '=', a list appears, where you can choose a component. Now you can move down with arrow keys or you can press the shortcut 'CA' to jump to the capacitor. Press enter, and the capacitor is shown on your work sheet. Now you can move, rotate and mirror it until you have it in the right position. Press enter. It is now fixed in its position and a window appears where you can set all parameters of the capacitor, including a label. Now you can press '=' again and insert the next component of your circuit and so on. If this is finished, you can connect all components with wires by pressing the space key.

Now you can analyse the circuit. For example you can let PaCi draw the Bode diagram. You press Menu,A,A for menu/analysis/AC analysis and then move the cursor to 'Bode diagram'. After pressing enter, you have to enter a few parameters for the diagram: frequency range, number of points to be calculated. If you now click on 'Calculate', the diagram will be calculated (that takes about 5-30 secs, depending on how much has to be calculated) and displayed. You can print the diagram or export as HPGL file (this can also be done with the circuit itself, of course!).

You can let show the Bode diagram for both amplitude and phase characteristics of the circuit.

Of course, it's also possible to calculate the transfer function or time function of a circuit.

It's also possible to watch the transient behaviour of a circuit: For example, if you create an RLC-circuit

----[R]----[L]------|-C-|--------------------and you want to know the output voltage if you switch the inoput voltage from 0 to 1, you can do this by pressing menu/analysis/transient analysis and set a few parameters. If you then press 'calculate', PaCi will show you a nice diagram looking like this:

........................where the x-axis shows the time and the y-axis shows the output voltage. (the diagrams PaCi draws are much prettier than my ASCII-drawings!)

PaCi also has a built-in text editor which you can use to place text (own descriptions or functions created by PaCi) into the current graphic (circuit or diagram).

Further features I didn't use by now:

- Optimization of parameters of a circuit: You can give special parameters the circuit has to have and PaCi can calculate the best values for components.

- poles and zeros diagram for circuits

- built-in interpreter: it allows to define arbitrary formulas and then draw them on the screen. In additin to the standard mathematical functions several auxiliary functions and access to the component parameters of the actual circuit are provided.

I think I now have covered the most important features of PaCi.

If you have further questions about PaCi, please contact Tamas Feher at This email address is being protected from spambots. You need JavaScript enabled to view it..

If you would like to purchase PaCi, please contact Petra Dudas at This email address is being protected from spambots. You need JavaScript enabled to view it..

(these email addresses may be obwolete by now, since this article is now over 10 years old!)

Please note that I am just a satisfied customer of DesignSoft, I am not involved into DesignSoft in any way.

## Screen shots

Here you can see a few screen shots of Palmtop Circuit:

A common RLC-circuit:

The Bode diagram of the RLC circuit:

The phase characteristics of the RLC-circuit

the transient analysis of the RLC-circuit:

PaCi calculated the transfer function of the RLC-circuit and showed it in the text editor. I wrote a few words above the function. Sorry - must be ´calculated´ not ´capculated´! ;-)

I put the contents of the text editor onto the work sheet under the circuit. Now I could print the whole sheet.

Another circuit designed with PaCi: A Colpitts oscillator: