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Hewlett Packard HP-35

Hewlett Packard  HP-35
Hewlett Packard  HP-35 in hand

Hewlett Packard HP-35

Distinctive features: The first hand-held scientific calculator.

On April 14th 2009 Hewlett Packard was awarded the IEEE Milestone in Electrical Engineering and Computing for the HP-35 calculator for the first hand-held scientific calculator.

Technical details:
Display is scientific, 10 digits mantissa and 2 digits exponent, red LED.

Scientific, using Reverse Polish Notation (RPN) - as evidenced by the lack of an "=" key.

Main integrated circuits in this example - Mostek MK6020, MK6021, MK6022, MK6023, MK6024, which comprise three ROMs, a control and timing chip, and a register and arithmetic chip.  This chip set was also second-sourced by AMI (American Micro-systems Inc.).

3.75v (3 x AA re-chargeable).

79 mm x 147 mm x 34 mm (3.1" x 5.8" x 1.4").

Introduced February 1972, cost $395 (about £165 GBP).

Made in U.S.A. & Singapore.

The calculator illustrated is an early example since it has no model number on the front, just 'HewlettPackard', since this was the only hand-held calculator then marketed by Hewlett-Packard.  Later examples are labelled with the model number—'HewlettPackard 35'.

Hewlett Packard  HP-35

With the casing taken apart the circuit board with the integrated circuits is revealed.

The press release for the award of the IEEE Milestone in Electrical Engineering and Computing for the HP-35 calculator says "Introduced in 1972, the HP-35 was the world's first handheld-sized scientific calculator.  An instant hit, the HP-35 ultimately made the slide rule, which had previously been used by generations of engineers and scientists, obsolete.

The HP-35, named for its 35 keys, was the first handheld calculator to perform transcendental functions such as trigonometric, logarithmic and exponential functions.

In the first three years after its introduction in 1972, sales of the HP-35 Scientific Calculator exceeded 300,000 units."

This was the first hand-held scientific calculator.  Previously, for their calculations, engineers and scientists would have used a slide-rule or a large desktop electronic scientific calculator.  Now they could use a pocket-sized electronic calculator, if they could afford the price or persuade their company to provide one.  Hewlett Packard calculators were very well made, and reliable, and their electronics instruments have always had a very good reputation.  Together with the high specification, this made their calculators the models of choice for many professionals.  In total, 300,000 HP-35 calculators were sold[1].

The cost of the HP-35 put it out of reach of many such as poor students, so other companies started to introduce scientific calculators with lower specifications and lower cost.  While nearly all of the other calculator manufacturers concentrated on reducing the cost of their calculators, Hewlett-Packard largely maintained the cost and increased the functionality.  They launched the HP-65, the first hand-held programmable calculator, in 1974, though they did introduce their own lower specification and cost scientific calculator in the HP-21 in 1975.  Hewlett-Packard are one of the few companies to continue making calculators from the early 1970s to the present day.

 

There is a lot of interesting information available about the HP-35, including:

 

 

Hewlett Packard awarded the "IEEE Milestone in Electrical Engineering and Computing" for the HP-35 calculator

On April 14th 2009 Hewlett Packard announced that it had been awarded the prestigious "IEEE Milestone in Electrical Engineering and Computing" for the HP-35 calculator, the first hand-held scientific calculator.

Presentation

Left to right presenting the IEEE HP-35 Milestone Award are: Lewis Terman (IEEE), Dave Cochran (HP-35), Richard Gowen (IEEE).

Plaque

The press release explains:

"Introduced in 1972, the HP-35 was the world's first handheld-sized scientific calculator. An instant hit, the HP-35 ultimately made the slide rule, which had previously been used by generations of engineers and scientists, obsolete.

The HP-35, named for its 35 keys, was the first handheld calculator to perform transcendental functions such as trigonometric, logarithmic and exponential functions.

In the first three years after its introduction in 1972, sales of the HP-35 Scientific Calculator exceeded 300,000 units.

An IEEE Milestone plaque recording the award will be permanently displayed at HP Labs in Palo Alto, Calif., the site where the HP-35 was originally developed."

HP 35s

July 2007: Hewlett Packard launches Retro HP 35s to Commemorate 35th Anniversary of First HP Handheld Calculator. More information on the Vintage Calculator News page.

Photograph of HP35s used with permission of HP.

Reference:

  1. Valéry, Nicholas, "The electronic slide-rule comes of age", New Scientist, 27 February 1975, p506-511.

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