# HP-41C

> programmable scientific RPN handheld calculator, produced by Hewlett-Packard from 1979

**Wikidata**: [Q629522](https://www.wikidata.org/wiki/Q629522)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/HP-41C)  
**Source**: https://4ort.xyz/entity/hp-41c

## Summary
The HP-41C is a programmable scientific RPN handheld calculator produced by Hewlett-Packard starting in 1979. It succeeded the HP-67 and HP-97 models and was notable for its expandability through magnetic card readers and peripherals. The calculator was used by astronauts during NASA's Space Shuttle program.

## Key Facts
- Produced by Hewlett-Packard from 1979
- Successor to HP-67 and HP-97 programmable calculators
- Uses postfix (RPN) notation for calculations
- Features a liquid-crystal display and computer keyboard interface
- Contains a central processing unit, non-volatile memory, and optional magnetic card reader
- Used by astronauts and NASA during the Space Shuttle program
- Followed by the HP-42S model
- Classified as both a calculator and mobile device
- Manufactured by Hewlett-Packard, an American IT company founded in 1939

## FAQs
### Q: What made the HP-41C different from earlier HP calculators?
A: The HP-41C was the first HP calculator to offer expandability through peripherals and magnetic card readers, allowing users to add new functions and store programs externally.

### Q: What type of notation does the HP-41C use?
A: The HP-41C uses Reverse Polish Notation (RPN), a postfix notation system where operators follow their operands, which was a hallmark of HP's scientific calculators.

### Q: Was the HP-41C used in space?
A: Yes, the HP-41C was used by astronauts during NASA's Space Shuttle program, demonstrating its reliability and advanced functionality for critical applications.

## Why It Matters
The HP-41C represented a significant advancement in handheld computing when it was released in 1979. As the first expandable HP calculator, it introduced the concept of modular computing to portable devices, allowing users to add new capabilities through peripherals and magnetic storage. This expandability, combined with its scientific RPN functionality, made it a powerful tool for engineers, scientists, and students. Its use in the Space Shuttle program underscored its reliability and advanced capabilities, while its influence extended to future calculator designs. The HP-41C helped establish HP's reputation for creating durable, professional-grade scientific tools that could handle complex calculations in demanding environments.

## Notable For
- First expandable HP calculator with modular peripheral support
- Used by NASA astronauts during Space Shuttle missions
- Introduced magnetic card storage for programs and data
- Advanced scientific functionality with RPN notation
- Durable design suitable for professional and space applications

## Body
### Technical Specifications
The HP-41C features a liquid-crystal display for clear numerical output and a computer keyboard interface for input. It contains a central processing unit that executes instructions and non-volatile memory for data storage. The calculator can optionally include a magnetic card reader for external data storage and program loading.

### Expandability Features
Unlike its predecessors, the HP-41C was designed with expandability in mind. Users could connect various peripherals through dedicated ports, and the optional magnetic card reader allowed for program storage and transfer. This modular approach was revolutionary for handheld calculators of the era.

### Usage and Applications
The calculator found widespread use in engineering, scientific research, and education due to its advanced mathematical capabilities. Its most notable application was in space exploration, where it was trusted by NASA astronauts for calculations during Space Shuttle missions, demonstrating its reliability under extreme conditions.

### Historical Context
The HP-41C was released during a period of rapid advancement in personal computing and portable electronics. It represented HP's commitment to creating professional-grade tools that combined portability with powerful functionality, setting a standard for future scientific calculators.

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## References

1. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
2. Freebase Data Dumps. 2013
3. National Library of Israel Names and Subjects Authority File