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Canon F-5

Date of introduction:  April, 1974 Display technology:  LED-stick
New price:   Display size:  8
Size:  5.4" x 3.1" x 1.4"
 138 x 78 x 37 mm3
    
Weight:  8 ounces Serial No:  517382
Batteries:  4*NiCd AA Date of manufacture:  year 1974
AC-Adapter:   Origin of manufacture:  Japan
Precision:  8  Integrated circuits:  Rockwell A4001-15471
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

The Palmtronic F-5 is a very unusual calculator manufactured by Canon. It was introduced mid of the year 1974 like the Texas Instruments SR-16 or the SR-50

F-5_PCB.jpg (69375 Byte)The F-5 combined due to its Rockwell calculator chip the functions of the SR-50 with the inaccuracy of the SR-16! A similar poor performance could be found in the huge Palmtronic F-7

The same housing was used with the rare FC-80 metric conversion calculator and the more common LE-81M and LE-100 basic calculators introduced in the same time frame. Later products like the LE-83 used a much cheaper construction. 

The next calculator in Canon's scientific line was the F-6 with a complete new housing. 

The F-5 wasn't the only "TI-less" calculator sold by Canon in the early days, view the odd LE-81. The last calculator with a TI brain was found with the Palmtronic F-31.

Running Mike Sebastian's "Calculator forensics" gives an unacceptable bad result of 10.4382 instead the expected value close to 9.0000. This places the F-5 in the league of boring calculators like the Canon F-6 (12.199423) and the never released SR-40 prototype (10.271817).

Another known side effect of the poor algorithm of the Rockwell calculator chips could be discovered with the unusual [ax] key:

Keystrokes

Results

[3] [ax] [3] [=] 27.00005

Rockwell uses - like most other companies - the equation:
ln(ax) = x * ln(a) to calculate the xth power of a.

It is easy to proove:

Keystrokes

Results

[3] [F] [ln] 1.098613
[*] [3] [=] 3.295839
[F] [ex] 27.00005


If you have additions to the above article please email: joerg@datamath.org.

Joerg Woerner, December 5, 2001. No reprints without written permission.