# HP-21

> Scientific calculator by Hewlett-Packard

**Wikidata**: [Q17513359](https://www.wikidata.org/wiki/Q17513359)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/HP-21)  
**Source**: https://4ort.xyz/entity/hp-21

## Summary
HP-21 is a scientific calculator manufactured by Hewlett-Packard featuring light-emitting diode (LED) display technology. It represents one of Hewlett-Packard's contributions to the calculator market during its operational years from 1939 to 2015.

## Key Facts
- HP-21 is a scientific calculator manufactured by Hewlett-Packard
- HP-21 uses light-emitting diode (LED) display technology
- Hewlett-Packard was an American information technology company founded in 1939 and ceased operations in 2015
- HP-21 is an instance of a calculator (as classified in knowledge bases)
- The calculator has documentation on Wikipedia in multiple languages: commons, English, French, and Japanese
- HP-21 has a sitelink count of 4 across different Wikimedia projects
- A visual representation of HP-21 is available on Wikimedia Commons
- Hewlett-Packard was headquartered in Palo Alto, California

## FAQs
### Q: What type of calculator is HP-21?
A: HP-21 is a scientific calculator designed by Hewlett-Packard for performing scientific calculations. It features light-emitting diode (LED) display technology.

### Q: When was Hewlett-Packard, the manufacturer of HP-21, founded?
A: Hewlett-Packard was founded in 1939 and ceased operations as an independent company in 2015, though its calculator division was part of its broader technology products.

### Q: In which languages is information about HP-21 available?
A: Information about HP-21 is available on Wikipedia in multiple languages including English, French, Japanese, and on Wikimedia Commons.

### Q: What display technology does HP-21 use?
A: HP-21 uses light-emitting diode (LED) display technology for showing numbers and calculation results.

## Why It Matters
HP-21 represents Hewlett-Packard's contribution to the scientific calculator market, demonstrating the company's expansion beyond its original focus in test equipment and computing systems. Scientific calculators like the HP-21 democratized complex mathematical calculations for students, engineers, and scientists, making advanced computational tools accessible outside of specialized laboratories. As a product of Hewlett-Packard, one of Silicon Valley's pioneering companies, the HP-21 calculator contributes to the broader narrative of technological advancement in the 20th century. It exemplifies the transition from mechanical calculators to electronic devices with specialized functionality, a trajectory that would eventually lead to graphing calculators and mathematical software.

## Notable For
- Being a scientific calculator manufactured by the pioneering Silicon Valley company Hewlett-Packard
- Featuring light-emitting diode (LED) display technology, which was a significant technological advancement at the time
- Having documentation across multiple Wikipedia language versions, indicating its recognition in the international knowledge ecosystem
- Representing Hewlett-Packard's expansion beyond its original test equipment and computing products into specialized calculators

## Body
### Manufacturer
HP-21 was manufactured by Hewlett-Packard, an American information technology company that operated from 1939 to 2015. The company was headquartered in Palo Alto, California, and at its peak employed approximately 302,000 people (as of 2014). Hewlett-Packard was recognized as a leader in the computer hardware industry, software industry, and information technology sector.

### Product Classification
HP-21 is classified as a calculator in knowledge bases, specifically categorized as a scientific calculator. Scientific calculators are designed to perform operations that are beyond the capabilities of basic calculators, including trigonometric, logarithmic, and exponential functions.

### Technical Specifications
HP-21 utilizes light-emitting diode (LED) display technology. LED displays were a significant advancement in calculator technology when HP-21 was introduced, offering better visibility and longer battery life compared to earlier technologies.

### Documentation
Information about HP-21 is documented across multiple Wikimedia projects:
- Wikipedia in English, French, and Japanese
- Wikimedia Commons with an image available at: https://commons.wikimedia.org/wiki/Special:FilePath/Taschenrechner_HP-21.jpg

The calculator has a sitelink count of 4 across different Wikimedia projects, indicating its presence in the knowledge ecosystem but with relatively limited documentation compared to more prominent technologies.

### Recognition
HP-21 has a Freebase ID (/m/0114p9ht) and is recognized as a distinct entity in knowledge bases, distinguishing it from other calculators and products manufactured by Hewlett-Packard. Its inclusion in multiple Wikipedia language versions suggests that it holds significance in the history of calculators or Hewlett-Packard's product line.