I got an HP33C in 1981 when I went off to university. Sadly, the battery and charger are long-gone, and the battery was some kind of proprietary rechargeable pack. Are replacements available?
You might check eBay for rebuilt battery packs. There are people who specialize in rebuilding battery packs for old calculators.
You’ll find HP41 emulators for window, palm, DOS, etc. I use the windows version (V41) daily, when my old 41 isn’t handy. One of these days I’ll see if synthetic programming* works on it.
I’ve been using RPN so long, that I basically can’t use an AOS (algebraic operationg system) calculator for more than a single operation.
*The 41 used variable length instructions. Through some hoop jumping it is possible to combine bytes in ways that are not available through the user interface, creating some useful instructions. This is/was called synthetic programming.
HP41 emulator? :: ears perk up ::
I lusted after that calculator when I was in high school. That and the Sharp EL-5100*. I used to draw them in my sketchbook. (I had it baaad…)
[sub]*And Kathy S. But that’s a whole other file.[/sub]
I wanted this for a long, long time, but once I found a few stack calculators for Windows, I realized that it didn’t work as well as I had hoped.
One of the biggest strengths of RPN on a calculator is that you don’t need to spell out each command - you just press the button associated with it, or if you’re scripting, press quote then the command button.
This, unfortunately, is a huge weakness on a computer. There is no convenient equivalent on a computer using an alphanumeric keyboard (unless you count clicking on on-screen buttons with the mouse, but personally I think that slows me down, which defeats the purpose of RPN.) I have yet to see a practical alternative to typing in each command.
I have found that, for myself, infix algebra works well on the computer. This is especially true given my background as a computer programmer - most code I’ve written is in algebraic infix form. One calculator program I’ve found which outshines most others is SpeQ - it has a ton of functions and lets you define your own, it handles variables, and one-variable plots. (My only complaint is that it doesn’t do parametric plots.)
I’d love to use a RPN calculator, and it looks a lot easier than algebraic notation to enter, but can someone explain to me, in small simple terms, how RPN works?
See also the Wikipedia entry; personally, I’d recommend reading the Example section first.
I’m EXTREAMLY familier with the HP41 (been using the same one for ~25 years) so my explaination may or may not be a general one, but the concepts are what matter.
It is based on a “stack”. (LIFO, last in first out). The 41 has a four number stack, with the positions labled X,Y,Z, and T (for top). When you punch in a number, it goes into X What you see on the display is the value in X.
HPs have a button labled “enter”, usually with an upward arrow following. That button “pushes” the value from X into Y, from Y into T, and the value in T is lost.
The arithmetic operation keys mostly operate on the values in X and Y and leave the result in X. Y gets “operated into” X, and Z “falls down the stack” into Y, and T similarly into Z. T is then loaded with zero.
How you use this:
On a AOS (“normal”) calculator, to add 7 and 8 requires the following key sequence:
Clear 7 + 8 = ( 5 keystrokes)
with RPM this becomes:
7 enter 8 + Only 4 keystrokes. big deal you say.
How about
(7+8)/(15+12)= 15 keystrokes (counting clear)
vs:
7 enter 8 + 15 enter 12 + / 11 keystrokes.
One thing RPN allows me avoid is rearrainging algebraic equations. Suppose I know a relationship as:
(A+B)/(C+D)=(E+F)/(G+H)
and I know all the values except E. I simply punch in:
A enter B + C enter D + / G enter H + * F -
and have my result (E)
A real example of this I often use is the relationship between resonant frequency and inductance (L) and capaitance © which I know as:
f=1/ (2pi(sqrt (LC)))
So if I have a 1000pF capacitor, what inductance is required to resonate it at 1.2 Mhz?
1.2E6 1/x 2 / pi / square 1000E-12 /
and I have my desired result: 17.6 microHenrys
Essentially, RPN allows me to mentally rearrainge the equation on the fly. AOS would require (me anyway) rearrainging the equation on paper, then punching the values in.
[QUOTE=Hari Seldon]
The ordinary folks 'round the world don’t understand stacks and RPN.
They do understand arithmatic, i.e. A X B = C. QED.
Now that is a great idea. Get a Patent pronto, if you can. It may have been sewed up a long time ago. [Even a conspiracy! :rolleyes: ]
I have an HP 48G emulator for my macintosh. Sadly the website I got it from was quickly removed. I’m guessing copywrite infingement. Its the only calculator I use. Sadly the two 48SX calculators I have have developed some screen defects and require pressing against the edge of the screen to get certain keys to work.
I had a 12C that I had in college in the mid-1980s. I bought it for the astronomical sum of something like $70.
During one move, the LCD screen got bashed in. I figured I would wait until the price dropped and pick up another (it’s consumer electronics, right).
I’m still waiting.
On the other hand, you use an RPN calculator the way you would work out a problem with a pencil. The operation “write down the first number, then write down the second, then add them” translates directly to “enter the first number, then enter the second (you do need to use Enter to separate them), then hit the ‘+’ key.”
The problem with me trying to use an algebraic calculator is that I’m always losing intermediate results. I’ll come up with a result, then think “I need to add five to that,” so I hit the ‘5’ key, and then realize that my previous result is now lost.
This thread inspired me to fire up my old 41C that I got in January of 1981 when I was a junior in college. So I went to Radio Shack, bought four Type N batteries, and it works like a champ. It feels like going home, and it’s wierd how much I remember.
I was quite happy to see that the default Calculator that came with my iBook had an RPN mode.
HP really put a great programming language into the 28 and 48 series calculators: RPL, or “Reverse Polish Lisp”. (“Reverse Polish Notation” is what RPN stands for. It means that operators follow operands, as in a stack machine. Lisp is a very powerful programming language.) I can do things in RPL that are flatly impossible in the BASIC dialects programmable AOS calculators use: Creating functions on the fly and passing functions around as data are extremely powerful and important techniques for solving problems. I use an HP-48GX myself, and RPL is one of my favorite programming languages. It’s significantly nicer than the majority of ‘industry-standard’ languages in current use.
Programmers who want an experience similar to RPL without downloading an HP simulator (or buying a real calculator) should check out Joy.
15C here as well. We all had to buy one on our first year in college (1986-7). Years later it was stolen and I got a… 22C I think. Thing is, the 15C was returned (I came back to class from the cafeteria and there it was, lying on top of my books all placid) so now I have both.
Now that looks pretty damn nifty. Thanks, Derleth.
That sounds like an insult. I think the later calculators had had “Reverse Polack Harelip.”
That’s nothing. Casio calculators are programmed in “Upside-down Kraut Hydrocephaly.”
Nerd alert:
I have:
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An HP 35 purchased in 1973, cost me $300 bucks (a lot of money then, had to sell my motercycle to get it) It still works with the battery charger, sadly no rechargable battery though, held together with duct tape. LED’s for the display still work fine. Still have the plastic case, leather holder and instruction manual.
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A 41cx from the 80’s. Ran this one over with my truck in the 90’s, but it’s padded case saved it’s life. A bit of plastic popped off the side but I still use it.
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A 48G purchased for sinkid in the 90’s. Her teacher sent a note home saying sinkid couldn’t use it in class because it wasn’t a scientific calculator. :smack: I had a little chat with the teacher and found that she had never heard of RPN, nor the order of operations in mathematics. Sinkid was eventually allowed to use the calculator after she showed the teacher she could get the same answers as teach did on her idiot TI.
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Three or four 32S II’s. We just kept buying them and losing them and refinding them again.
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And a K & E 4083-3 with hyperbolics!!!
and the standard leather belt holder of course.