Why HP 42S for Electrical Engineering?

[lemontea]

I've read that the "best" calculator for Electrical Engineering is the 42S.

Why is this? Or at least, why do those people hold that opinion?

Don't some of the other ones have EE equations or can be programmed properly?

[rprosperi]

(05-31-2017 11:51 PM)lemontea Wrote:  I've read that the "best" calculator for Electrical Engineering is the 42S.

Why is this? Or at least, why do those people hold that opinion?

Don't some of the other ones have EE equations or can be programmed properly?

It's likely that what was stated was the 42S is the best RPN Calculator from HP for EE work. Relatively few HP RPN machines have Complex number support built-in, I think only the 32S, 32SII, 33S (but who cares), 35S and 42S. Of these, the 42S is definitely the most capable machine, largest memory, larger addressable screen, etc.

The RPL machines (48/49/50 series) are far more capable, but they're RPL, which differs greatly from RPN. A comparison is really more of a religious discussion than a technical one, however, as you have some 48 machines, I guess you know that.

Also the WP-34S (which although based on HP h/w cannot be considered an HP machine) has superior precision, more integrated complex support and a far broader set of math functions, so it's probably better for EE work as well (not sure, I'm an ME), however the shoddy keyboard and limited LCD of the underlying 20b/30b hardware makes it a very frustrating machine to use at all, at least for me.

[lemontea]

I see. That makes sense (the RPN aspect versus RPL). Thanks!

(Just a note, the 15C has Complex mode, but it is quite complex to use! Haha!)

[pier4r]

(06-01-2017 12:57 AM)rprosperi Wrote:  The RPL machines (48/49/50 series) are far more capable, but they're RPL, which differs greatly from RPN.

Could you elaborate on this? For my little knowledge, Rpl is a superset of rpn (well mostly) in terms of what one can do, so I don't understand your statement.

[lemontea]

(06-01-2017 06:05 AM)pier4r Wrote:  

(06-01-2017 12:57 AM)rprosperi Wrote:  The RPL machines (48/49/50 series) are far more capable, but they're RPL, which differs greatly from RPN.

Could you elaborate on this? For my little knowledge, Rpl is a superset of rpn (well mostly) in terms of what one can do, so I don't understand your statement.

The way you program the calculators is different.

On the 15C (and I assume all other "RPN" calculators) you enter Program mode through g + P/R (Program/Run mode change). I also have the 11C and it works the same.

Then, f LBL A (program label A), then enter the sequence of keystrokes you want to execute. Then you end with R/S (run/stop). And exit Program mode (P/R).

Now you enter your variables onto the stack or store them, and run program A, f A (or, in USER mode, just press A).

On the 48G series, you do not do this.

You create a program OBJECT.

That object is delimited by << and >>

You type the program object onto a single line, which would basically be the same sequence you entered into the 15C.

Now you ENTER that and put it onto the stack.

Now, press ' (single quotes) and type in the program name (basically, the variable to which you want to store this program object), and ENTER.

Program object is now Stack Level 2, and program variable name is Stack 1.

Press STO (store).

Now it's stored.

To execute it, you can simply display all your variables, with the VAR key.

The program you just stored is now a softkey and can be executed just by pressing the relevant softkey.

So you can put your values onto the stack, and simply press the softkey, done!

(The 48 method is the same as the 49 and 50g method.)

RPN in this case is not used to describe the RPN entry method. ALL HP calculators (sorry, except for the algebraic ones which I keep forgetting about) use the RPN entry method (with the stack).

There was no name for the non-RPL programming so people just called it RPN programming.

[emece67]

If my memory serves me well, the 42S may be the first (and only) hp RPN machine with fully integrated support for complex matrices. In this respect, neither the 15C nor the 41 (with any hp module) can compete here, they cannot, for example, compute the determinant of a complex matrix, although they can solve a system of linear, complex equations.

Also, although being a big fan of the wp34s, it cannot compete with it in this respect.

Being an EE, I bought my first hp machine (a 28C) when at the university just to solve circuits, it was, then, the only calculator fully supporting complex matrices. Later I switched to the 48SX and to the 42S. Nowadays, not needing such capability anymore, I rely on both the wp34s and DM15L for my everyday work, assisted by a 48GX (in fact by an Android emulator) when dealing with units.

So, IMHO, the 42S may be, really, the best RPN machine for EE students.

Regards.

[BartDB]

My first HP calculator as an EE student was the HP-28C, considered the first RPL calculator. A year later I upgraded to the 28S which I used up to about 8 years ago when the battery door failed completely, I then got a 50g.

I've tried the 42S, but in my opinion it's no match for the RPL calculators. Perhaps the only advantage is a more compact size.

I now mostly use a computer, but have a 50g on the side.
.

[Logan]

I'm a EE (PE) and use the 42s exclusively as my desk calculator, though honestly I use the computer for most things.

The main advantages for EEs is its complex number format and its matrices handling. The programming capability is outstanding too, I just programmed multiple radar equations in the other day so I could see the attenuation effects of rain and etc. and all in a few minutes while in a meeting

For a practicing EE, I personally think graphing calculators are overkill and needlessly cluttered. For more complex things I'm going to use MATLAB or Excel, I just need a robust scientific calculator for hand calculations.

But for a student, the 50g is certainly more capable and will have its own advantages in being able to graph and check integrals. I used a TI-89 in school and being able to solve simultaneous equations (in any format) was certainly the main advantage I saw. Graphing something during the exam was another.

[pier4r]

@lemontea : understood but you described how storing a program is different in the 42s and on the 48.

My point was another : aside from small differences, to me it seems that both the 42s (I'm using free 42) and the 50g share the same approach and most of the functions.

[Ángel Martin]

(06-01-2017 07:02 AM)emece67 Wrote:  If my memory serves me well, the 42S may be the first (and only) hp RPN machine with fully integrated support for complex matrices. In this respect, neither the 15C nor the 41 (with any hp module) can compete here, they cannot, for example, compute the determinant of a complex matrix, although they can solve a system of linear, complex equations.

I think you're correct, although I was under the impression that the Advantage Pac could do complex determinants as well...

But I must say that the best machine for EE's is the HP-41 with the 41Z module - that's the real killer app for complex support ;-) - even if it doesn't do complex determinants either but can be done with a very short Z-FOCAL program ;-O)

Cheers,

[Luigi Vampa]

On my desk at work, and literally every day, I use a Free42 incarnated in the body of a Kindle Fire 7" + Android 5.1 OS, no FireOS :P The total budget was €49*. Although you can't enjoy the tactile feedback of the keys, the level of details in the retina skins are a joy to the eye, even with this tablet's 1024x600 pixels 'a la cheapo' display.

Regarding my HP48sx and HP28s... well, too-high sentimental value in both of them, so I keep them safe and sound. HP50g's SolveSys program makes it a dream for any engineer, but I use the HP50g virtual calculator to run the programs I write at home with my physical calculator. I seldom, if ever, take my HP50g out of home, because I don't want to pack more stuff in my backpack:
- Laptop + charger
- Tablet (meant to run 'ol reliable Free42) + compact charger
- Raspberry Pi 3 (meant to simulate number-crunching designs in Mathematica) + battery pack

I work as EE for a Chinese engineering company and my colleagues from China aren't used to RPN at all. The ease of use of Free42's solver is what is most striking to them! :O) Besides, Free42 handles problems in complex domain just 'out of the box', there is no need of additional modules or programs.

*[EDIT] Plus Thomas' Free42 donation.

[Gerson W. Barbosa]

(06-02-2017 01:07 PM)Luigi Vampa Wrote:  HP50g's SolveSys program makes it a dream for any engineer, but I use the HP50g virtual calculator to run the programs I write at home with my physical calculator.

On the HP-28S, this program was a joy to use during Circuit Analysis examinations:

http://www.hpmuseum.org/cgi-sys/cgiwrap/...ead=180091

Regards,

Gerson.

[Dwight Sturrock]

7 good reasons:

1. Complex # support
2. Matrices
3. Alphanumeric
4. Excellent solver
5. Easy programmability
6. Alphanumeric program labels
7. HP41 compatibility