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Texas Instruments TI-25

Date of introduction:  1978 Display technology:  LCD
New price:  $27.95 Display size:  8 (5 + 2)
Size:  5.3" x 2.9" x 0.35"    
Weight:  3.0 ounces Serial No:  40850
Batteries:  2*LR44 Date of manufacture:  mth 05 year 1978
AC-Adapter:   Origin of manufacture:  Japan
Precision:  9 Integrated circuits:  Toshiba T3763
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner
    Download manuals:   (US: 6.7 MByte)
  (EU: 18.6 MByte)

With the TI-25 Texas Instruments entered in 1978 the market of scientific LCD-calculators. On a first view the TI-25 looks like one of the later slimline models TI-50 or TI-35 but it is totally different. This calculator was  produced in Japan in opposite to the later US origin of the slimline models and is somewhat larger. 

TI-25_1_PCB.jpg (116525 Byte)TI-25_1_IC.jpg (120494 Byte)The electronics of the TI-25 is based on a Toshiba design with only 9 digits of calculating precision instead of the later US designs with 11 digits precision. Comparing the TI-25 with the Toshiba SLC-8260 gives the impression that the whole calculator is is a Toshiba design.

The first version of the TI-25 was soon replaced with a design using the PN1033734 calculator chip. Find more information here. Don't miss a rare TI-25 with a yellow polarizer for the liquid crystal display.

Don't miss the Toshiba SLC-8300, the first scientific calculator using a yellow LCD.

If we trace back the routes of Toshiba calculator chips within the TI-line, we evaluate:

Type Model Introduction First Toshiba IC
Basic TI-1750 (1st) year 1977 T3532, year 1976
Basic SLR TI-1766 year 1981 T6789, year 1981
Scientific TI-25 year 1978 T3636, year 1977
Scientific SLR TI-30 SLR year 1982 T6824, year 1982
Financial none   T6787, year 1982
Financial SLR BA-SOLAR year 1986 T7917, year 1986


It took only a short time between the introduction of a Toshiba calculator chip and the corresponding Texas Instruments calculators. For the financial calculators TI used between the years 1978 and 1986 always their own chips, the missing link could be found with the Canon Financial calculator.

It was not unusual for Texas Instruments to start an epoche with Japanese technology and move later to US developments. You'll find similar approachs from the TI-1750 to the TI-1030.


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

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