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Recommendations for RPN Calculators?
sg3000 asks: "My trusty old HP 48S graphing calculator, that served me since engineering school, seems to be giving up the ghost. I haven't used it in a few years, but recently I put new batteries in it. It works, but it makes a loud static/white noise sound when it's on. The noise is not as noticeable when I hold it, but when I set it down on a hard surface, it's really loud. Then it sucks the batteries down incredibly fast (I put new batteries in it, and two days later, they were drained). Any suggestions on what I should buy as a replacement?"
"I'm in graduate school now, and since I'm taking an accounting course, where they don't want us digging out our laptops during a test, I need to buy another calculator. I'm a big fan of reverse polish notation (RPN), so I'd prefer to get another HP calculator.
Do companies still make calculators? I'd love to get another HP 48, but I'm not even sure if HP even makes calculators like that any longer -- on their web site, they're all cheapo-looking single line deals. I've read about something called an HP 48g, but HP has nothing about it on their web site."
Sounds like its power supply inverter is toast. Rip it apart, trace down the IC that is making all the noise (or look for a small IC mounted xformer near on IC) and do some home work. Replace what makes noise and what ic is a PWM if it has one, unless its home brew PWM inversion and learn.
The RPNs worth buying are:
16C - awesome calculator for programmers, especially embedded work. There is no better number system converter available at any price. No I can't do bin/dec/hex in my head faster than the 16C and neither can you. Expensive due to relatively low numbers produced.
42S - pricey, even used, but excellent. Two line display, a replacement for the 15C.
32SII - somewhat like a 42S but with single line display, not so nice to use.
15C - same form factor as 16C. At the time HP's top scientific.
11C - a simpler 15C
10C - a simpler 11C
All the above have solid old-HP build quality, excellent key feel and outstanding battery life.
Older HPs are also usable (and may be preferred) - but they have even greater collector status and sometimes fetch higher prices. They will go through batteries faster and the red LEDs can be harder to see.
Forget the 48 models, the 49 and all the new stuff. The 48GX is OK if you have to have graphing but the single and dual-line models have better UI for daily use. The 49? HP died when Carly took over. Now they make pretty colored plastic boxes that only work with windows and they have forgotten how to spell "engineering". In fact they fired all the engineers and HP is now run by MBAs in shiny suits.
(I own 16C, 42s, 15C and 11C models.)
This sounds like subharmonic oscillation in the inductor core used in the DC-DC converter. Pop it open, find the inductor, and replace it - thing should be good as new.
Absolutely untrue. They're made by the same calculator division that worked on calculators before HP spun off Agilent. It's just that Agilent got the calculator division.
The division was rebranded, not the calculator.
Jeremy
Looking for a Python IRC bot?
I'll have to disagree with your statement that "TI just doesn't cut it." True, their low to mid range graphing calculators (e.g., 73, 85, etc.) can't compare to any of the HP's current (or past) graphing calculator offerings. However, the TI-92 PLUS and TI-89 can very much hold their own in comparison to the HP's.
My primary calculator is the TI-92 PLUS (I used to use a TI-85) and the HP 48 series can't beat the ease of the TI-92 PLUS in terms of entering/performing symbolic operations. What do I use it for? I use it to check that I haven't made a mistake in my pencil and paper grunge work (i.e., arithmetic or algebraic manipulation [my level of math is well beyond calculus so basic algebraic manipulations are considered somewhat grungy]).
The symbolic manipulation of Mathematica is vastly superior to that of the TI-92; however, it is inconceivable that I have ready access to my laptop or another public computer that has Mathematica on it. So, in those moments, I whip out my TI-92 to verify that I didn't make a silly error such as sign dropping or whatever in those calculations which require a page long worth of algebraic manipulation.
Reverse Polish Notation?!?!? Why exactly is it "Polish"?
Because a Polish man came up with the idea?
Prefix and Postfix notation were developed in the 1920's by Jan Lukasiewicz (who was, in fact, Polish). Prefix notation was often called Polish Notation in honor of Lukasiewicz.
Postfix turned out to be useful for computer operations, if you made it into a stack and then did operations upon that stack. It was called Reverse Polish Notation, since postfix is the opposite of prefix, and prefix was called Polish Notation.
Simple.
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
I agree that keypresses saved are minimal, if not sometimes nonexistant in simple equations. In fact, for many simple single-operation equations, the process of learning RPN is far too complicated to justify using it at all.
RPN, however, can be likened to the Dvorak keyboard layout. It is entails a slightly involving process to learn. For many purposes, this is simply a pain. The true power only shines in complicated equations, such as those which make use of brackets.
The following equation shall be typed on an algebraic calculator, followed by an RPN calculator. [;] will be the button name for [Enter].
25 ( 46 ) + 254 - 2462 / ( 645 - 2453 )
Algebraic:
25*46+254-2462/(645-2453);
RPN:
25;46*254+2462;645;2453-/-
In the above example, you will realise that the number of keypresses is exactly the same. (In fact, if you cheat and leave out the second bracket on the algebraic calculator, that calculator edges out the RPN by one keystroke!) However, there are three immediate benefits to the RPN calculator:
Over time, the amount of keypresses will not really be changed too drastically. However, the true power is the convenience and the ease of use. Unfortunately, like the Dvorak keyboard, RPN will slowly fade in the non-specialised markets due to the fact that it takes too much time to learn.
And there are many occasions where the graphing functions of my TI have proved useful in the workplace. To name a few:
- being able to view every key I've entered before evaluating the expression
- being able to revise and edit incorrect expressions
- to determine linear regression fits for data sets
- to perform functions like logarithms and square roots on said data sets, in order to linearize them (linearity being checked, of course, by the R^2 correlation of my fit)
- anything at all to do with linear algebra, especially solving systems of equations or matrix manipulations. RREF is a bitch by hand.
For more "pure" math (like Diff. Eq.), I agree that pencil and paper are generally easier. But any applied math (a.k.a. engineering) requires an insane amount of busy work that could not be handled with a puny scientific calculator. I know you said Engineering and Physics are different stories, but everything I just wrote could certainly apply to all sciences (even the "soft" ones like Psych. and Sociology), or anything at all requiring data collection.
For the record, I use a TI-86 daily at a bio-tech job. It has the stats capabilities of the 83, plus all the good parts of the 85.
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