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
|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:||CD4507 or CD4557|
|Program steps:||Courtesy of:||Joerg Woerner|
|Download manual:||(US: 6.3 MBytes)|
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 hybride between a slimline and slanted calculator.
Dismantling this TI-40 manufactured end of 1981 in Abilene, Texas reveals the CD4557 single-chip calculator circuit known from the second generation of the TI-35. We spotted in earlier models of the TI-40 a 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: email@example.com.
© Joerg Woerner, December 5, 2001. No reprints without written permission.