DATAMATH CALCULATOR MUSEUM

Texas Instruments TI-1205

Date of introduction:	1976	Display technology:	LED-stick
New price:		Display size:	8
Size:	5.5" x 2.8" x 1.4"
Weight:	5.5 ounces	Serial No:	1016188
Batteries:	2 * AA NiCd	Date of manufacture:	wk 19 year 1977
AC-Adapter:	AC9130	Origin of manufacture:	USA
Precision:		Integrated circuits:	TMS0972
Memories:
Program steps:		Courtesy of:	Kirk B. Muri

Texas Instruments took in 1976 in conjunction with mathematics educators at two major universities an initiative to introduce a group of 6 calculators for educational use. Including the Little Professor, the limited function ABLE calculator, the colorful TI-1205 and TI-1255, the TI-30 and the sophisticated SR-51-II, these calculators helped students understand and use math concepts from kindergarten through college and career.

The TI-1205 is based on the TI-1200 but includes rechargeable NiCd-batteries instead the standard 9V block battery. To enhance the readability of the keyboard both the size of the numerals and the color-scheme was improved.

Disassembling the TI-1205 reveals an internal construction identical with the TI-1255. Instead of the 9V battery found in the original TI-1200, TI-1250 design, the TI-1205 makes use of 2 rechargeable, AA-sized NiCd (Nickel Cadmium) batteries. The PCB (printed circuit board) adds both the charging circuit for the batteries and a step-up converter to generate the 9V supply of the TMS0972 single-chip calculating circuit. Please notice that both the Klixon™-style keyboard and the TMS0972 would support the 4-key memory of the TI-1255.

The TI-1205 is by far the most colorful and exotic calculator within the TI-12xx line.

Don’t miss the Spirit of '76 and TI-1260 using the same white color housing

Kirk, thanks for opening your rare TI-1205 !

Find here an excerpt from the TI Learning Center brochure CB-272 dated 1976:

TI-1205. Four function capability for upper elementary students.

Ideally suited for use with Texas Instruments 4-6 grade level “Elementary Mathematics Concepts with Calculators™” learning kit, the rechargeable TI-1205 meets all the criteria for beginning use of full-function calculators as described in the December 1975 Newsletter of the National Council of Teachers of Mathematics.

The TI-1205 features a colorful face with large, easy-to-read numerals. A bright, 8-digit display shows calculator overflow indication, and a negative sign, just to the left of displayed numbers. The TI-1205 adds, subtracts, multiplies, divides – all in full-floating decimal. And there’s an automatic constant for multiplication/division of a series of numbers by one number to or from a series of numbers.

Algebraic entry lets students enter numbers and press keys as they would write them on paper. Clearly labeled, easy-to-handle keys provide a positive “click” to assure students that a number has been entered. A separate clear entry key lets them clear a mistake without repeating the entire problem.

When used in conjunction with 4-6 grade level “Elementary Mathematics Concepts with Calculators”, developed by the University of California ’s Lawrence Hall of Science, the TI-1205 can be a positive force in acquisition of mathematical concepts by upper elementary students.

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