What's the current go-to calculator for electrical engineers?

[amwales]

Why did it take this long to find SpeedCrunch? Thanks, looks awesome

[armandine2]

HP35s for me. 

Its good to have a new HP calculator with their build quality - I'm a bit disappointed with the 35s dedicated P-R omission. And generally the P-R and R-P ease of use on a calculator might be a good starting point for an electrical engineer's calculator.

On that user point I've just worked out how to get R-P and P-R on an old Casio fx-180P calculator I was put onto from another forum - used in a fluid mechanics problem .

[kripton2035]

I just bought a used hp prime, and it is stuck in exam mode... plug it in a computer as it should remove the exam mode, but no.
seems it doesn't work if you connect to a mac computer... I tried some old pc's I have and same problem.
I even format the internal drive, this thing is still stuck in exam mode
is there a way to reset it factory ? thanks.

Just to be clear, it’s not plugging it into a computer that ends exam mode, it’s plugging it into a computer and using the appropriate command in the HP Prime Connectivity Kit software to turn off exam mode.

On the Mac, the newest version of the connectivity kit software doesn’t run on older OSes (but will still install!) so be sure to check the system requirements and use an older version if necessary. HP’s FTP server still has all the software: ftp://ftp.hp.com/pub/calculators/Prime/

I installed the last, then older versions of the hp connectivity kit on my mac, and the hp prime is not shown on the usb events...
so the calc doesn't appear, and I can't end the exam mode... will have to try on a pc, but I only have very old ones, and a virtual machine on the mac doesnt see the prime either.
the calc is charging though with the same cable ...

[tooki]

Try a different cable. You could have a shoddy or failed cable, or perhaps even one designed only for charging. Or the calculator’s USB port could be damaged, which would be unfortunate.

[kripton2035]

Try a different cable. You could have a shoddy or failed cable, or perhaps even one designed only for charging. Or the calculator’s USB port could be damaged, which would be unfortunate.

you are absolutely right... I thought the cable was specific to this calculator, but not it's a simple usb to micro-usb cable. I tried another cable and it exited the exam mode !!!
more to know: I did not have to launch the hp connectivity kit for that, only connecting the cable removed the exam mode.

[tooki]

Try a different cable. You could have a shoddy or failed cable, or perhaps even one designed only for charging. Or the calculator’s USB port could be damaged, which would be unfortunate.

you are absolutely right... I thought the cable was specific to this calculator, but not it's a simple usb to micro-usb cable. I tried another cable and it exited the exam mode !!!
more to know: I did not have to launch the hp connectivity kit for that, only connecting the cable removed the exam mode.

Oh really? I stand corrected. I was going by what I read somewhere.

[bson]

I also use the HP prime, but finding programs for it is a bit harder. Do you know if there is any website dedicated to it?

I too use the HP Prime for basic arithmetic in RPN mode.  It's nice because of its backlit display and good keyboard.

I took a look at it for programming and found it utterly useless.  Unlike HP calculators of the past programs don't operate on the stack but instead are expected to prompt for input and display output.  Not exactly an engineering tool anymore.  In fact, it seems the calculator is just another program even if implemented in C and compiled to native ARM code and not part of the "system". 

Otherwise my go-to calculator is Mathematica.

[Berni]

I also use the HP prime, but finding programs for it is a bit harder. Do you know if there is any website dedicated to it?

I too use the HP Prime for basic arithmetic in RPN mode.  It's nice because of its backlit display and good keyboard.

I took a look at it for programming and found it utterly useless.  Unlike HP calculators of the past programs don't operate on the stack but instead are expected to prompt for input and display output.  Not exactly an engineering tool anymore.  In fact, it seems the calculator is just another program even if implemented in C and compiled to native ARM code and not part of the "system". 

Otherwise my go-to calculator is Mathematica.

The TI Nspire calculators are pretty similar to HP Prime.

They are built from various applications like an imediate calculator, graph, spreadsheet, text editor...etc that can open up in tabs to let you quickly switch between them and copy paste data around. One of them is a script editor that lets you write programs in a scripting language (lua i think).I don't think it ever supported running native ARM code, but as always with these calculators people have created a custom bootloader that allows you to do that.

I have the old non backlit B/W display model of the TI Nspire that i used to help me get trough university. The contrast on that LCD was horrendous and was only usable in a well lit room, but then again i also found that useful because i would often cheat by loading up a bunch of text files over USB. Overall it is a pretty impressively powerful calculator. Most of the reason why i bought it over the classical TI-89 or an HP is because it will take pretty much any math problem written into it 1:1 as it is on paper and solve it. No need to put things into correct form, just give it a system of equations with any variable names you want, burry them under complex numbers, exponents, whatever... and at the push of a button it will spit out the solution to all the variables. In the case of a underdefined system it will simply include the unknown variables as part of the result. If you suddenly want to constrain a variable to be pure imaginary then you simply add another equation to the system that says Re(x)=0

That being said as impressive as the capabilities of that calculator are, it still was kinda cumbersome and slow to type in stuff. So i kept a regular scientific calculator around for the quick easy stuff. These days even that calculator is gathering dust because i use SpeedCrunch for everything now.

[armandine2]

Museum of HP calculators has some good HP Prime programs -

just programmed BESS1 into my HP Prime - simple program for Bessel functions of the 1st kind.

[tooki]

I also use the HP prime, but finding programs for it is a bit harder. Do you know if there is any website dedicated to it?

I too use the HP Prime for basic arithmetic in RPN mode.  It's nice because of its backlit display and good keyboard.

I took a look at it for programming and found it utterly useless.  Unlike HP calculators of the past programs don't operate on the stack but instead are expected to prompt for input and display output.  Not exactly an engineering tool anymore.  In fact, it seems the calculator is just another program even if implemented in C and compiled to native ARM code and not part of the "system". 

Otherwise my go-to calculator is Mathematica.

They make no secret of the fact that its math engine is based on the open-source Xcas. I don’t know the exact software stack, but I actually doubt it’s native ARM, since the exact same code runs on their desktop (Intel) calculator simulator, so I think there’s some abstraction layer.

[Just_another_Dave]

They are built from various applications like an imediate calculator, graph, spreadsheet, text editor...etc that can open up in tabs to let you quickly switch between them and copy paste data around. One of them is a script editor that lets you write programs in a scripting language (lua i think).I don't think it ever supported running native ARM code, but as always with these calculators people have created a custom bootloader that allows you to do that.

I’m not sure, but the limitation to run compiled code might be related to the exam mode (running native code might allow bypassing it). Those limitations are a bit annoying, as those calculators could be more useful for engineering if they could interact with lab equipment or run completely custom programs (the hp prime can actually be used as a data logger using HP StreamSmart 410, but just with some Fourier sensors, making it almost useless in a real lab). It would be interesting if TI or Hp created a model targeted towards engineers without any of the limitations imposed for allowing it being used in exams

[Berni]

The decision to not run machine code executable is probably more because they don't want to put the effort into developing it as a feature.

If this was a feature then they would need to provide a SDK for developing apps, create friendly APIs for interfacing to the hardware, document all of it, make it all robust enough to not blow up if an app does something stupid. The thing probably runs on more of a RTOS type OS in there so if an app crashes it would likely take the entire calculator with it. Or even worse an app could probably mess things up enough where it runs but other features of the calculator do weird stuff and bug out(making there own product look bad).

Putting in lua scripting instead gives you a "walled garden" where the program can only talk outside where you provide an means to do it. As a bonus you can also write the script on the calculator itself without having a compiler on board.

[tooki]

The two major generations of HP Prime hardware run different software stacks. The G1 runs some proprietary OS from the OEM who manufactures it, the G2 runs FreeRTOS.

Presumably atop that is the interpreter or whatever it is that actually runs the Prime “OS” if you will.

My hunch is that they basically have 4 lower-layer host OSes: the G1’s thing, FreeRTOS, Windows, and Mac. Above that I think it’s the same software, since software versions are the same across them, even bugs apply equally to all of them.

Probably makes sense to ensure mathematical results don’t vary depending on the underlying hardware, as well as allowing for exam mode, etc.

[armandine2]

Museum of HP calculators has some good HP Prime programs -

just programmed BESS1 into my HP Prime - simple program for Bessel functions of the 1st kind.

Graphing with it though was beyond me - Excel (Ed. for me) was unsurpassable!

[Berni]

Graphing with it though was beyond me - Excel (Ed. for me) was unsurpassable!

I don't think i ever used the graphing functionality of my TI Nspire graphing calculator to ever do anything useful. For me it was mostly a machine for solving systems of equations no matter how weird and complicated of a system.

[armandine2]

Might even be interesting to try out the TI Nspire, on its (Vernier) lab cradle using the voltage and ammeter sensors,  in the data logging mode.
 I should get around to doing it - having bought the gear! 

[SparkyFX]

casio fx991ex

The solar cell feature is awesome. Battery lasts a decade or more easily.

There is also an app with a similar user interface: https://play.google.com/store/apps/details?id=uk.co.nickfines.RealCalc&hl=de&gl=US

edit: I am old, i was referring to a somewhat similar FX992s here.

[mansaxel]

casio fx991ex

The solar cell feature is awesome. Battery lasts a decade or more easily.

There is also an app with a similar user interface: https://play.google.com/store/apps/details?id=uk.co.nickfines.RealCalc&hl=de&gl=US

edit: I am old, i was referring to a somewhat similar FX992s here.

I have a Sharp EL-506p. It's on its first set of batteries. It was bought in 1984, by my mother, for me.

Batteries probably are very toxic, but if one has to swap them every 35 years and there are better ones now, I'm OK with that.

[SiliconWizard]

I have a Sharp EL-506p. It's on its first set of batteries. It was bought in 1984, by my mother, for me.

Batteries probably are very toxic, but if one has to swap them every 35 years and there are better ones now, I'm OK with that.

This calculator works on LR44 button cells.

They certainly contained a small amount of mercury, which was the case for pretty much all button/coin cell batteries AFAIK, and even a lot of other types of primary batteries.
Mercury-free batteries are a relativey "recent" trend due to environmental regulations. You can absolutely find mercury-free LR44 batteries these days. They may not last as long as 35 years, but they'll be good enough.

[PlainName]

Got a Casio FX-450 in the garage which hasn't seen daylight in 20 years or so. I am fairly sure I bought it around 1987, so it's about 34 years old. It will still power on just from the overhead (now not very bright) 2ft fluorescent tube over the bench, although nowadays I am reluctant to use it in case the hinge gives up.

[BreakingOhmsLaw]

Well, this thread blew up unexpectedly. Thanks to every contributor for their input. I have bought an HP Prime now and so far I'm very happy with it. Still learning to drive it, but it is really nice.
I've meddled with RPN a bit, but really can't understand the often quoted advantage that it is less buttons pushes. Having to push the space button to separate operator eats up this advantage, at least for simple operations, which make up the majority of day-to-day use.
Of course on more complex operations, I can see that it has its charms.
That said, with the possibilities of the HP Prime, you would probably be even more productive just creating a program for the job.
Going to order an 991 as well, just to have a backup in the drawer.

[Berni]

The RPN thing is mostly because old calculators often used it and people got used to it, especially the financial calculators, then HP used it on a lot of calculators too and they got pretty popular too. People get used to it and just prefer it.

Similar to the new dual row scientific calculators with cursors. People who are used to the classic ones usually don't like them. However i am young enough that the new dual row ones ware already around back when i was in school, so i much prefer the new ones. I don't have the mental muscle memory to think about order of operations when keying stuff into a calculator, since these modern calculators do that on there own. I also make lots of use of the cursor where i go back and try modifying a value and quickly get the result recalculated, or go back up the history list and grab something i already typed in previously to save me the time. This is why i love SpeedCrunch on the PC, it works in a similar way. In my opinion this is how things should work since we are no longer bound by limitations of 80s consumer LCD display technology.

So the ideal calculator is really a lot about personal taste.

[bson]

It's not about pressing fewer buttons, it's about ease of chaining calculations.  Especially calculations involving multiple results.  Even your typical algebraic calculator isn't strictly algebraic, for example you press 45 SIN to calculate a sine.  Because if you have a result from a previous calculation, like 45, and want the sine of that it's cumbersome to turn it into SINE(45).  Many algebraic systems, like Mathematica, have a history and can refer to previous values, so you might say Sin[%14] to accomplish the same.  In effect, the stack is exactly a "history" of calculations, or a notepad you can operate on.  Something like Mathematica, while superior, would be very difficult to use meaningfully in a calculator form factor.

[TimFox]

I like my Swiss Micros (link posted above in my earlier response) DM41X that uses RPN and displays the four-line stack.

[kripton2035]

because of this thread, I bought a used hp prime and I really begin to like it.
what I like most is the big tactile screen, you can tap on a result, scroll up/down, copy and the selected formula is at the input again.
very nice and speedy.