DATAMATH CALCULATOR MUSEUM |
Texas Instruments TI-40
Date of introduction: | 1982 | Display technology: | LCD |
New price: | $25.00 | Display size: | 8 (5+2) |
Size: | 5.8" x 3.1" x 0.90" 147 x 79 x 23 mm3 |
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Weight: | 3.7 ounces, 106 grams | Serial No: | 2885585 |
Batteries: | 2*LR44 | Date of manufacture: | wk 45 year 1981 |
AC-Adapter: | Origin of manufacture: | USA (ATA) | |
Precision: | Integrated circuits: | TP0455/CD4507 or TP0456/CD4557 | |
Memories: | 1 | ||
Program steps: | Courtesy of: | Joerg Woerner | |
Download manual: | (US: 6.3M Bytes) |
This TI-40 looks somewhat odd. If you compare it with the TI-55-II you notice that the upper line of keys is missing. The advantage of the TI-55-II compared with the slimline calculators like the original TI-35 was the bigger display and the extra line of keys. And now this one - the electronics and the display of a slimline calculator in the slanted housing.
Difficult to understand, but on Texas Instruments' production lines in 1982. Roughly four years later we received with the slanted TI-53 again a hybrid between a slimline and slanted calculator.
Dismantling
this TI-40 manufactured end of 1981 in Abilene, Texas reveals the
TP0456/CD4557
single-chip calculator circuit known from the second generation of the TI-35. We
spotted in earlier models of the TI-40 a TP0455/CD4507 chip.
Read more about the "CD4507+50=CD4557" equation here.
If you are interested in the calculating accuracy of scientific calculators don't miss the Calculator forensics.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.