Bowmar 901B

Date of introduction:  September 1971 Display technology:  LED-stick
New price:  $240 Display size:  8
Size:  5.2" x 3.1" x 1.5"
 133 x 78 x 37 mm3
Weight:  10.9 ounces, 310 grams Serial No:  28445
Batteries:  6*AA NiCd Date of manufacture:  mth 02 year 1972
AC-Adapter:  7.2V 225mA DC, 7.0V 45mA AC Origin of manufacture:  USA
Precision:  8 Integrated circuits:  TMS0103, 2*SN75491, 2*SN75492
Memories:   Displays:  Bowmar Optostic
Program steps:   Courtesy of:  Joerg Woerner
    Download manual:   (US: 2.3M Bytes)

With Monsanto introducing the first commercial LED (Light Emitting Diode) display in 1970 and Texas Instruments announcing on September 17, 1971 the "calculator-on-a-chip", Bowmar/Ali Inc. of Acton, Massachusetts, USA launched the famous 901B "True-Pocket-Size" calculator based on the TMS0103 with a suggested retail price (SRP) of $240.00.

It took less than one year before Texas Instruments announced the TI-2500 Datamath calculator in April 1972 with a SRP of only $149.95, its delivery in June 1972 to first customers in the Neiman-Marcus and Sanger-Harris department stores in Dallas, TX and its formally introduction on September 21, 1972. The SRP of the TI-2500 was reduced to $119.95 by the date of its introduction.

Dismantling the featured Bowmar 901B manufactured in February 1972 reveals not only the TMS0103, but four Texas Instruments display drivers, the original Klixon™ keypad and a Bowmar-made Optostic LED display.

This calculator was sold under different labels, beside this Bowmar 901B it was popular as Commodore C110 and Craig 4501, too.

Compare this Bowmar 901B with the Mariner NRC7200 sporting LED displays from Monsanto.

Digging in the history of portable electronic calculators? Don't miss the Sanyo ICC-804D, Sharp EL-8 and Rapidman 800.

Later with the Bowmar 901D a similar calculator with a 10 digit display was sold.

A very similar design was introduced by Columbia with the Scientific. Don't miss the minirex 73, the Eastern copy from GDR company RFT and the Heathkit IC-2009. The Litronix Checkmate looks similar but is completely different.

If you are familiar with the Klixon™ keyboard, have a closer look on the following machines: All three calculators were manufactured by Texas Instruments and use this keyboard:

Longines Symphonette EC
Montgomery Ward P800
Radio Shack EC-100

Compare this 901B with later products like the MX55.

Bowmar Instruments was one of the first casualties of the Calculator Wars and filed in 1976 for bankruptcy. Don't miss a mystery calculator with the Bowmar brand introduced in 1977!

Klixon™ is a trademark of Texas Instruments.

horizontal rule

If you have additions to the above article please email:

© Joerg Woerner, December 5, 2001. No reprints without written permission.