Each of the four models of the Wang series 400 calculators incorporated functions particularly suited for a specific discipline. The Model 450-1 Calculator was designated as “Basic Scientific.” The 450-1 could be programmed by use of the numeric keypad and a set of special function keys whose location brings to mind the function keys found on today’s PCs. Programs could alternatively be loaded by use of an optional device that read punched or mark-sense cards. The specialized functions that especially suited the Wang 450-1 for general scientific applications, what Wang called “personality,” was provided by a plug-in discipline-specific circuit board containing read only memory (ROM) programs. Results from calculations were provided on a Panaflex display atop the keyboard comprised of a series of twelve neon bulbs with filaments, portions of which could form numerals from 1 to 9 as well as 0. The Model 450-1 Wang Calculator was actually quite expensive: when first introduced in 1972 it cost $1,300, or almost $7,400 in 2012 dollars.
This calculator was used by Dr. Earl Stadtman (1919–2008), recipient of the 1979 National Medal of Science for his work on anaerobic bacteria and enzymology, during his years of work as the chief of the Laboratory of Biochemistry at NHLBI. [04.0009.003]
The HP-35 was the first pocket-sized scientific calculator, allowing scientists to abandon their slide rules for good. Named for its 35 keys, the HP-35 was the first scientific pocket calculator when it was introduced in 1972. The development of metal-oxide-semiconductor integrated circuits in the early 1970s made it possible to shrink the technology necessary for complicated calculations—at a price. Due to the high cost of the new circuits, the HP-35 debuted at a steep $395, but that didn’t prevent 100,000 units from being sold during its first year in production. In addition to its cutting edge circuits, the HP-35 also used new Light Emitting Diodes (LEDs) in its screen.
Prior to the release of the HP-35, pocket calculators could perform only the four basic arithmetic functions, and slide rules were used for exponential and trigonometric functions. The HP-35 was able to reduce calculation times by almost 80%, effectively making the slide rule obsolete. In recognition of its revolutionary effect on the work of scientists and engineers everywhere, the HP-35 was awarded the IEEE Milestone in Electrical Engineering and Computing award in 2009. This particular calculator was used by Dr. Michael Channing, then a radiochemist, then later the group chief of the Radiopharmaceutical Production and Quality Control group in the Positron Emission Tomography department in the NIH Clinical Center. [06.0007.001]
The Hewlett Packard HP 35, launched in 1972, is generally recognized as the first portable scientific calculator. But Texas Instruments, home of the invention of integrated circuits, launched its reply to the HP 35, the SR 50, in early 1975. As it was expensive to produce, it was soon replaced by the SR 51, which incorporated some cost-saving modifications. The liquid crystal display in the SR 50, for example, was replaced by a smaller CD bar behind a magnifier bubble. The SR 51A was promoted as a scientific-financial calculator in recognition of the higher mathematical capability. The SR 51A was capable of performing both trigonometric and statistical operations. The keyboard contained 20 keys for performing arithmetic, and an additional 15 keys are devoted to higher mathematical functions. The calculator was also equipped with a random number generator. The SR51A, like its counterpart the HP 35, has been credited with ending the long dominance of the slide rule for technical calculations. This model of calculator was introduced in June 1975 for $224.95. The “A” in the model number means that it was identical to the SR-51 model except it had no inner rigid keyboard frame, LED display, or bubble-lens magnifier, making it a cheaper high-end calculator. This calculator was used by Dr. Marshall Nirenberg, who won the Nobel Prize for breaking the genetic code. [10.0001.004]
By adding an alpha key to enable the keyboard to go between the alpha and normal keyboard modes, this calculator made inputting programs and functions easier. Functions could also be typed in with the “User” key and assigned to a specific key. The 41C also increased the amount of memory available in its predecessor, which could also be expanded with memory modules. The card reader had a translator for programs written for the HP 67. Hewlett Packard made the 41C from 1979 to 1985. This calculator pictured here belonged to Dr. Kenneth J. Rothman, founding editor of the journal Epidemiology. Rothman was working at the NIH National Cancer Institute in 1979 when he co-authored ”Epidemiologic Analysis with a Programmable Calculator” with Dr. John D. Boice, Jr. Later editions of the book [13.0013.002] referred specifically to this calculator model. [13.0013.001]
