New to HP48GX

[simba15]

So a recent WTB thread enlightened me about the HP48GX series.

Very cool! not affordable lol, good thing there is an Android simulator.
Using EMU48.

I really only want to it for use of the electrical equations. Only thing is I have no idea how to use it!

I have scanned through the quick start and programming manuals, and found the EQ LIB but no where shows how to enter data/complete the equation.

I always get error (dup error or circular reference or too few arguments) I just want to 120v/10A lol (12ohm)

Any advise would be appreciated. (please hold the shame as I am new to the HP48), Thanks.

[george.b]

I always get error (dup error or circular reference or too few arguments) I just want to 120v/10A lol (12ohm)

The HP48 series are RPN calculators. If you want to do 120 divided by 10, you enter 120 [ENTER] 10 [÷].

Or, if you meant to do it by using the equation library: Right shift, 3 (EQ LIB), make sure UNITS isn't selected, go to Ohm's Law, A softkey (SOLV), 120, A softkey (V), 10, B softkey (I), left shift, C softkey (R) works for me.

[simba15]

Yes the RPN style is a bit different at first glance, (but then just look at as a you were doing it by hand)

Thanks for the direct key presses it was the left shift that I was missing ( what is this doing? putting into solve mode?)

Thanks!

[Bicurico]

RPN is very easy.
You have a stack, which is like four lines. You enter numbers and they get put in the stack. Numbers that are already in the stack get moved one line up.
If you now select an operation, it will need one, two or more lines of input.
For example: you press multiply. This will multiply the value on line one with number on line two. The result is put in the first line and everything that was after the second line is put in the second line forward, so the void is removed.
With the HP48GX the stack is unlimited, so there are not just 4 lines in the stack, but an unlimited amount.
Going further, you can have a function that expects the stack to contain certain types of information in each lines.
Also, a line in the stack can contain a function.
Any line in the stack can be stored in a variable, so you store a number or a program in the same way. After getting used to it, it is very powerful and you won't want to go back to regular calculator programming...
I call it lines in the stack, but they have names like X, y, t, s. Not sure what they stand for.

[BeBuLamar]

They are X,Y,Z and T. T is the top and duplicates itself when it drops. The HP48's don't have names for the stack they are just level 1, 2, 3 etc... as they are basically limited by the amount of memory. I suggest that the OP download the EMU48 version for either the PC or Mac. They work just like the real thing. I have both a 48SX and 48GX but I prefer to use the emulator.

[rodcastler]

I would recommend you go through the thick manual. It's a piece of art in the sense that it walks you through everything with step-by-step examples so you actually train your brain on how to use it.

I find myself going back to the equation library, financial solver, fit data and unit conversion quite often.

There's no turning back after you get used to the 48GX. I not only have the emulator on the iPhone for everyday use, but I still have an actual HP in the drawer for once a week real-thing taste... and I graduated from college 22 years ago.

[george.b]

Thanks for the direct key presses it was the left shift that I was missing ( what is this doing? putting into solve mode?)

Yup, that selects which variable(s) you want to solve for. If you had done left shift + F softkey (ALL), it would have solved for both R and P.

Thanks!

No problem

[simba15]

Thanks all!

I am using EMU48 seems very good for a simulator (would love a real device, too bad there $$$ now)

Will be sure to go through the manual for some more tutorials

[SiliconWizard]

If you really want to get the real device one of these days, I'd suggest looking for the HP48G+ rather than the GX. It can be had for significantly less money, while being the same except that the G+ doesn't have an expansion port.

[simba15]

Thanks, I saw the G+ going for reasonable prices.

It includes the PC interface so that would be a great to have.

Anything to look for ( screen color?)?

Thanks.

[Picuino]

I suppose you already know the wonderful website https://www.hpcalc.org/ with plenty of resources for your HP programmable calculators (programs and documentation).
I have 2 HP 48 calculators and an HP 49. The HP48s are almost worth more now on the used market than when I bought them. It's a shame HP has stopped making them.

[SiliconWizard]

Anything to look for ( screen color?)?

Grab one with a black LCD rather than the blueish ones (but I'm not even sure the G+ was ever produced with those blueish LCD screens - to be checked), the black ones have much better contrast.