# deflection yoke

> kind of magnetic lens, used in cathode ray tubes (CRT) to scan the electron beam both vertically and horizontally over the whole screen

**Wikidata**: [Q322355](https://www.wikidata.org/wiki/Q322355)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Deflection_yoke)  
**Source**: https://4ort.xyz/entity/deflection-yoke

## Summary
A deflection yoke is a magnetic lens used in cathode ray tubes (CRT) to scan the electron beam both vertically and horizontally over the whole screen. It consists of copper coils and a plastic former that surrounds the rear neck of the tube. The deflection yoke is essential for directing the electron beam to create images on CRT displays.

## Key Facts
- Instance of: coil, electronic component
- Named after: yoke
- Used in: cathode ray tubes (CRT)
- Function: scans electron beam vertically and horizontally over the entire screen
- Aliases: yoke, yoke coil, deflection yoke, bobine de déviation magnétique, Ablenkeinheit, Umlenkjoch, Ablenkjoch, bobina defletora, unidade de deflexão
- Wikipedia title: Deflection yoke
- Commons category: Deflection coils
- Google Knowledge Graph ID: /g/11byz6zj4x
- Encyclopædia Britannica Online IDs: topic/deflection-coil, technology/deflection-yoke

## FAQs
### Q: What is a deflection yoke used for?
A: A deflection yoke is used in cathode ray tubes to scan the electron beam both vertically and horizontally over the entire screen, enabling the creation of images on CRT displays.

### Q: What are the main components of a deflection yoke?
A: A deflection yoke typically consists of copper coils and a white plastic former that surrounds the rear neck of the CRT tube.

### Q: What are some alternative names for a deflection yoke?
A: A deflection yoke is also known as a yoke, yoke coil, bobine de déviation magnétique, Ablenkeinheit, Umlenkjoch, Ablenkjoch, bobina defletora, and unidade de deflexão.

## Why It Matters
The deflection yoke is a crucial component in cathode ray tube technology, which was the dominant display technology for televisions and computer monitors for several decades. Without the deflection yoke, it would be impossible to direct the electron beam across the entire screen, making image formation on CRTs unfeasible. This component played a vital role in the development and widespread adoption of television and early computer displays, enabling the visual revolution that transformed entertainment, communication, and information technology. Although CRTs have largely been replaced by newer display technologies, the deflection yoke remains an important part of the history of electronic displays and continues to be used in some specialized applications.

## Notable For
- Essential component for image formation in CRT displays
- Enables precise control of electron beam scanning in both vertical and horizontal directions
- Unique magnetic lens design specifically tailored for CRT applications
- Multiple international names reflecting its global importance in display technology
- Integral part of the visual revolution in television and early computer monitors

## Body
### Technical Function
The deflection yoke operates by creating magnetic fields that bend the path of electrons in the CRT. These magnetic fields are generated by passing electrical currents through the copper coils. By varying the current in different parts of the coil, the yoke can control the direction of the electron beam with high precision.

### Physical Characteristics
The deflection yoke is typically cylindrical in shape, designed to fit snugly around the neck of the CRT tube. The copper coils are wound in a specific pattern to create the necessary magnetic fields for both horizontal and vertical deflection. The white plastic former provides structural support and insulation for the coils.

### Historical Context
Deflection yokes were developed as part of the broader evolution of cathode ray tube technology in the early to mid-20th century. They became a standard component in television sets and computer monitors from the 1930s through the early 2000s, when LCD and other flat-panel display technologies began to dominate the market.

### Current Applications
While largely obsolete in consumer electronics, deflection yokes are still used in some specialized applications, such as certain types of scientific instruments, medical imaging devices, and industrial equipment that utilize CRT technology. They also remain important in the study of display technology history and in the restoration of vintage electronics.