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HP Forum Archive 16

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FIX key on HP-12C
Message #1 Posted by karl gruber on 14 Oct 2006, 12:05 p.m.

How do I change how many decimal places are displayed on a HP-12C.

I don't see a "FIX" key.

      
Re: FIX key on HP-12C
Message #2 Posted by Antonio Maschio (Italy) on 14 Oct 2006, 12:12 p.m.,
in response to message #1 by karl gruber

f [n] where n = 1..9

-- Antonio

            
Re: FIX key on HP-12C
Message #3 Posted by Vieira, Luiz C. (Brazil) on 14 Oct 2006, 1:20 p.m.,
in response to message #2 by Antonio Maschio (Italy)

Hi, Antonio;

Quote:
f [n] where n = 1..9
We could add [f][0] and [f][.] to your list, being [f][.] the scientific notation.

My 2.

Luiz (Brazil)

Edited: 14 Oct 2006, 1:22 p.m.

                  
Re: FIX key on HP-12C
Message #4 Posted by Kalevipoeg on 14 Oct 2006, 2:43 p.m.,
in response to message #3 by Vieira, Luiz C. (Brazil)

I have compared f [n] of the 12C and fix [n] of the 11C.

For example we have a number 0.0012345

f [2] of the 12C gives 0.001

whereas

f fix [2] of the 11C gives 1.23x10^-3

Which way do you prefer?

Edited: 14 Oct 2006, 3:10 p.m.

                        
FIX display on business vs. scientific
Message #5 Posted by Karl Schneider on 14 Oct 2006, 3:51 p.m.,
in response to message #4 by Kalevipoeg

Kalevipoeg posted,

Quote:
I have compared f [n] of the 12C and fix [n] of the 11C.

For example we have a number 0.0012345

f [2] of the 12C gives 0.001

whereas

f fix [2] of the 11C gives 1.23x10^-3


f [0], f [1], f [2], and f [3] all display 0.0012345 as 0.001 on the HP-12C, as do the HP-10B, HP-14B, HP-17B, and HP-17BII. In effect, 0.001 is a "FIX 3" format.

That's a nice bit of insight into design principles of HP's business- and scientific-calculator models: The business calculators offer a limited choice of selectable display formats:

  • The HP-12C offers FIX [0]-[9] and SCI [6] (limits of 10-digit display)
  • The HP-10B offers FIX [0]-[9].
  • The HP-14B, HP-17B, and HP-17BII offer FIX [0]-[11] and ALL.

Of course, if the magnitude of a number is outside the range of the display using a FIX format, scientific notation with a base-10 exponent will be utilized. For numbers of small non-zero magnitude, these models will simply extend a FIX display format with more decimal digits as needed until the number can be displayed as a non-zero value.

The scientific models, by contrast, offer selectable scientific notation with a designated number of decimal digits -- SCI [n] and ENG [n], n = 0-9 or 0-11, as appropriate. So, they will revert to scientific notation with the same number [n] of decimal digits, if FIX [n] cannot represent a non-zero value using only [n] decimal digits.

So, why don't the HP business-calculator models use the procedure of the HP scientific-calculator models? Because to do so would often invoke a non-selectable display mode, and that scientific notation is generally avoided in business applications unless absolutely necessary.

There you have it. BTW, I prefer the procedure of the scientific models, but one should recognize that it is based on their built-in capabilities.

-- KS

Edited: 14 Oct 2006, 9:49 p.m.

                              
Re: FIX display on business vs. scientific
Message #6 Posted by Marcus von Cube, Germany on 15 Oct 2006, 4:16 a.m.,
in response to message #5 by Karl Schneider

Quote:
BTW, I prefer the procedure of the scientific models, but one should recognize that it is based on their built-in capabilities.

... and on the intended audience. Business people are (in most cases) not scientists and would wonder far too often what that strange display "1.23 -03" means: "Is my calc broken?". The display of "0.001" is easy to understand for them: "Oh, it's less then a cent!".

Marcus

                                    
Re: FIX display on business vs. scientific
Message #7 Posted by Karl Schneider on 15 Oct 2006, 3:13 p.m.,
in response to message #6 by Marcus von Cube, Germany

Hi, Marcus --

You posted:

Quote:
... and on the intended audience. Business people are (in most cases) not scientists and would wonder far too often what that strange display "1.23 -03" means: "Is my calc broken?". The display of "0.001" is easy to understand for them: "Oh, it's less then a cent!".

A very good point, and in fact the built-in capabilities are based upon said "intended audience".

Many modern low-end scientific calculators with a 7-segment display line for numerical results include a tiny "x10" annunciator just below and to the left of the exponent -- just to prevent any possible confusion...

-- KS

                              
Re: FIX display on business vs. scientific
Message #8 Posted by bill platt on 16 Oct 2006, 8:44 a.m.,
in response to message #5 by Karl Schneider

Karl,

That's a nice essay.

And it shows very well how much thoughtfulness went into the design of these machines. No wonder we are willing to mortage our houses for them;-)

regards,

Bill

                  
Re: FIX key on HP-12C
Message #9 Posted by Antonio Maschio (Italy) on 16 Oct 2006, 3:00 a.m.,
in response to message #3 by Vieira, Luiz C. (Brazil)

Luiz wrote:

Quote:
We could add [f][0] and [f][.] to your list, being [f][.] the scientific notation.

Of course...

-- Antonio

      
Re: FIX key on HP-12C
Message #10 Posted by Timespace on 14 Oct 2006, 12:13 p.m.,
in response to message #1 by karl gruber

'f' followed by 4 will give you 4 decimal places. 'f' followed by 2 will give you 2 decimal places....

            
Re: FIX key on HP-12C
Message #11 Posted by karl gruber on 14 Oct 2006, 3:42 p.m.,
in response to message #10 by Timespace

Thanks,

My eyes just couldn't find that in the owner's manual.......whose text size is too small.

Best wishes


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