HP-41 modules



I just released a new version of my HP-41 module database.
Feel free to download on:


Please, I'm also very interested in comments, additions, bug reports, ...



is there any way I can get a program on ohms law & pascals law ?
Thank You


Sure, here's a simple Ohm's Law program:

02 "I (AMPS)?"
04 "R (OHMS)?"
06 *
07 "E="
09 "|V"
10 END

(where "|" should be replaced by the append symbol)


is there any way I can get a program on ohms law & pascals law ? Thank You Dale

Eric's HP-41 program incorporates the well-known E = IR for DC systems or where E and I are "in-phase" AC quantities (purely-resistive systems). We AC power guys prefer E = IZ, where E, I, and Z are all complex-valued, and Z = R + jX. Unfortunately, the HP-41 was not designed with built-in complex-number support.

-- KS


I deprecate the use of programs for simple matters. You can't put an education in a calculator try as you might. Practice makes perfect is the law you should remember. I remember Ohmite made cardboard Ohms rule slide rules. Sam


I remember Ohmite made cardboard Ohms rule slide rules. Sam

I have two of those in my collection. One shows a 1949 copyright. The other shows a 1961 copyright. Both carry a price of 25 cents!

The features are the same including:

On the front side a 17 cm standard slide rule with A, B, C and D scales but without a cursor and a parallel resistance calculator.

On the other side an Ohm's Law Calculator which requires only one setting of the slide; for example, the user sets the ohms input opposite an arrow and reads the solution for various pairs of parameters from adjacent scales. Solutions include watts vs volts, milliamperes versus watts, volts versus milliamperes, watts versus amperes, and amperes versus volts.


I can provide a 42S version for AC power analysis. :-)


I can provide a 42S version (of Ohm's Law) for AC power analysis. :-)

And I have no doubt that you can... :-)

It's just that, when I see Ohm's Law stated as "E = IR" (or "V = IR", if you will), I'm compelled to comment that such an expression is only a limited subset of the general-purpose equation.

The comment is meant only for general interest, though, not as a correction.

-- KS


Hi Matthias,

Great work!

I have a few questions:

- Was the CCD B really provided in a CMT module, not a HP ROM module as for CCD A?

- I remember there was another version of the Ext-IL ROM (presumably older), the CAT 2 header was EXT IL1A instead of EXT IL ROM. I should still have a ROM image somewhere.

- Do you have ALL these modules? :-)



Hi, Matthias --

That's quite an impressive list of plug-in devices for expanding the HP-41's capabilities -- a testament to the versatility of the platform.

Thank you for preparing it.

-- KS

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