DATAMATH

DATAMATH CALCULATOR MUSEUM

Sharp QT-8D

Date of introduction:	October 1969	Display technology:	Fluorescent
New price:	$495	Display size:	8
Size:	9.8" x 5.4" x 2.8"
Weight:	3 pounds 3 ounces	Serial No:	151087
Batteries:		Date of manufacture:	year 1970
AC-Adapter:	220 V	Origin of manufacture:	Japan
Precision:	8	Integrated circuits:	Rockwell AC2261, AU2271, DC2266, NRD2256
Memories:
Program steps:		Courtesy of:	Joerg Woerner

If we trace the Time-line of calculating device starting from the early abacus and the Napier bones to the 20th century we get some important milestones:

• 1820 The Arithmometer
• 1874 The Ohdner calculator
• 1884 The Comptometer
• 1948 The Curta
• 1960 The first electronic calculators based on vacuum tubes
• 1964 The first transistor based calculators
• 1965 Texas Instruments started the Cal-Tech project leading
    to the first hand-held calculator prototype
• 1969 Sharp introduced with the QT-8D the first calculator using
    LSI-IC's (Large-Scale-Integration Chips) manufactured by
    US company Rockwell Electronics
• 1969 Sharp introduced the first battery operated desktop calculator QT-8B
• 1970 First battery operated, handheld calculators:
    Busicom LE-120, Canon Pocketronic, Sanyo ICC-82D and Sharp EL-8.
• 1971 First portable, battery operated calculator using a
    "Calculator-on-a-chip" appeared with the Bowmar 901B

Sharp Electronics Corporation introduced end of the year 1969 this important desktop calculator. A later version of the QT-8 (the QT-8B from 1970) included a rechargeable battery pack in order to make it portable. It is very similar to the first "really" portable, battery operated calculator, the EL-8.

Do get an impression about the valuable internal construction just take your time and watch the next five pictures carefully.

This photo gives you an idea of the sleek design of the calculator.
The display uses its own printed circuit board with the driving electronics.
The display is made from single tubes with odd segmentation.
The printed circuit board of the calculator brain shows the famous chip-set developed by US company Rockwell. The same chips are used in the smaller EL-8.
An impressive view of one of the Rockwell calculator chips. Only Rockwell used the staggered layout of the pins. The datecode 7025 on top of the gold hood gives a manufacturing date mid of 1970.

Read more about Sharp Corporation’s Calculator Innovations.

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