Canon F-55S

Date of introduction:  November 1979 Display technology:  LCD
New price:   Display size:  8 (5 + 2)
Size:  3.7" x 2.2" x 0.30"
 94 x 56 x 8 mm3
Weight:  1.6 ounces, 44 grams Serial No:  447029
Batteries:  CR2016 Date of manufacture:  year 1980
AC-Adapter:   Origin of manufacture:  Japan
Precision:  8  Integrated circuits:  Toshiba T3934S
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

The Palmtronic F-55S is one of the smallest scientific / statistical calculators ever developed. 

F-55S_PCB.jpg (202830 Byte)How was it possible to reduce a calculator like the TI-25 introduced in the same era to the size of a credit card ? Quite simple, the engineers of Canon reduced the keyboard dramatically using a sliding switch. The switch is located at the right of the display and connects one of the 4 associated functions to one row of 4 keys.

Adding the keys together gives 24 discrete keys plus 4 rows of 4 multiplexed keys equals 40 keys. The magic number of 40 keys is usual for the early Toshiba calculator chips with scientific functions. Count the keys yourself on the Toshiba SLC-8260 or SLC-8410.

Don't miss the F-55S in a silver housing.

If you have additions to the above article please email:

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