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DATAMATH CALCULATOR MUSEUM

Texas Instruments Little Professor (1978)

Date of introduction:	December 1978	Display technology:	LED-stick
New price:		Display size:	8
Size:	5.0" x 3.5" x 1.1" 127 x 89 x 29 mm³
Weight:	3.8 ounces, 107 grams	Serial No:
Batteries:	9V	Date of manufacture:	wk 36 year 1979
AC-Adapter:		Origin of manufacture:	USA (ATA)
Precision:		Integrated circuits:	TMC1993
Memories:
Program steps:		Courtesy of:	Joerg Woerner

You know this cute math trainer, the Little Professor. Millions and millions were sold in the past 2½ decades from this simple but funny educational product. The basic idea behind the Little Professor is opposite to a normal calculator: The child has to type the answer of simple questions like "3 + 5 = ?". You can choose between the four basic math functions and four different grade levels. If the child gives a wrong answer "EEE" occurs, otherwise another of more than 16000 different questions is asked.

From the technology this Little Professor from 1978 is similar to the TI-1000 calculator of the same epoch. This second version of the Little Professor could easily recognized at the [ON], [OFF] keys and the [LEVEL] key to adjust the grade level. Compare it with the Little Professor (1976).

Dismantling multiple Little Professor (1978) devices reveals a surprise - some models use inside a flexible printed circuit board (Flex-PCB) and some a Rigid-PCB. While the first version of the TI-1000 used a TMC1991 packaged in 28-pin SPDIP (Shrink Plastic Dual In-line Package) with Die-up (standard pinout) on a two-sided Rigid-PCB and the second version a TMC1992 packaged in 28-pin SPDIP (Shrink Plastic Dual In-line Package) with Die-down (reverse pinout) on a single-sided Flex-PCB, reversed the Little Professor (1978) the sequence:

• Little Professor (1978-1979): TMC1993 packaged in 28-pin SPDIP (Shrink Plastic Dual In-line Package) with Die-down (reverse pinout) on a single-sided Flex-PCB
• Little Professor (1979-1980): TMC1993 packaged in 28-pin SPDIP (Shrink Plastic Dual In-line Package) with Die-up (standard pinout) on a two-sided Rigid-PCB

Consequently the Little Professor (1978) from a later production (January 1980) with Rigid-PCB uses an "unmarked" TMC1993 while a Little Professor (1980) manufactured in September 1980 sports a chip marked TMC1993.

The 5^th row of the keyboard with the keys [OFF], [SET] and [LEVEL] disturbs the design of the Little Professor. Already in 1980 a new, smaller keyboard was available and this one matched the original design. The picture on the right combines this Little Professor (1978) with the later Little Professor (1980).

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