The HP-35, introduced by Hewlett-Packard in 1972, was a groundbreaking device that set new standards for scientific calculators. As the first pocket calculator capable of performing scientific functions,
its design and features were meticulously crafted to meet the needs of scientists and engineers. This article explores the technical aspects of the HP-35, highlighting its innovative design and the features that made it a revolutionary tool.
Innovative Design
The HP-35 was designed to be compact and portable, fitting comfortably into a shirt pocket. Its dimensions were 5.8 inches in length, 3.2 inches in width, and 0.7 to 1.3 inches in height, making it easy to carry and use on the go. Despite its small size, the HP-35 was packed with advanced technology that set it apart from other calculators of its time.
One of the most notable design features of the HP-35 was its red LED seven-segment display, which could show up to 15 digits. This display was capable of presenting a ten-digit mantissa and a two-digit exponent, allowing users to perform complex calculations with precision. The use of light-emitting diodes was a cutting-edge choice at the time, providing a clear and bright display that was easy to read.
Advanced Features
The HP-35 was equipped with a range of advanced features that made it a powerful tool for scientific calculations. It was the first pocket calculator to include trigonometric and exponential functions, enabling users to perform a wide variety of mathematical operations. The calculator's firmware was stored in 768 bytes of memory, allowing it to execute complex instructions efficiently.
A key feature of the HP-35 was its use of reverse Polish notation (RPN) for data entry. RPN allowed users to enter calculations in a more logical sequence, reducing the number of keystrokes required and minimizing errors. This feature was particularly beneficial for complex calculations, where accuracy and efficiency were paramount.
Power and Performance
The HP-35 was powered by an internal rechargeable battery, consisting of three AA-sized NiCd cells. This battery pack was removable, allowing users to replace it when necessary. An external battery charger was also available, and the calculator could operate directly from the charger, with or without batteries installed.
Internally, the HP-35 was built around a serial processor chipset, capable of processing decimal floating-point numbers with a ten-digit mantissa and a two-digit exponent. This processing power enabled the calculator to perform a wide range of functions, from basic arithmetic to complex scientific calculations.
The HP-35's design and features set a new standard for scientific calculators, combining portability with advanced functionality. Its innovative design and technical capabilities made it a valuable tool for scientists and engineers, paving the way for future advancements in calculator technology.
