# Wehnelt cylinder

> electrode in the electron gun assembly of some thermionic devices

**Wikidata**: [Q2554501](https://www.wikidata.org/wiki/Q2554501)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Wehnelt_cylinder)  
**Source**: https://4ort.xyz/entity/wehnelt-cylinder

## Summary
The Wehnelt cylinder is an electrode component in the electron gun assembly of thermionic devices, invented in 1902 by Arthur Wehnelt. It plays a key role in controlling electron beam focus and intensity in vacuum tubes and early electron microscopes.

## Key Facts
- Invented in 1902 by Arthur Wehnelt
- Part of the electron gun assembly in thermionic devices
- Classified as an electrode, functioning as an electrical conductor in vacuum environments
- Also known as the Wehnelt cap or focusing cylinder
- Named after its inventor, Arthur Wehnelt
- Used to control electron beam focus and intensity
- Found in applications such as vacuum tubes and early electron microscopes
- First documented in academic sources in 2013

## FAQs
### Q: What is the Wehnelt cylinder used for?
A: The Wehnelt cylinder is used to control the focus and intensity of an electron beam in thermionic devices like vacuum tubes and early electron microscopes.

### Q: Who invented the Wehnelt cylinder?
A: The Wehnelt cylinder was invented by Arthur Wehnelt in 1902.

### Q: What is another name for the Wehnelt cylinder?
A: It is also known as the Wehnelt cap or focusing cylinder.

### Q: In which devices is the Wehnelt cylinder found?
A: The Wehnelt cylinder is commonly found in the electron gun assembly of thermionic devices, including vacuum tubes and early electron microscopes.

### Q: What role does the Wehnelt cylinder play in an electron gun?
A: It helps control the electron beam's focus and intensity by adjusting the electric field within the electron gun.

## Why It Matters
The Wehnelt cylinder is a foundational component in thermionic devices, enabling precise control over electron beam characteristics. Its invention in 1902 by Arthur Wehnelt significantly advanced the development of vacuum tubes and early electron microscopes. By modulating the electric field, the Wehnelt cylinder allows for better focusing and intensity adjustment of electron beams, which is crucial for the performance of these devices. Its role in shaping early electronic and microscopic technologies highlights its importance in the history of electronics and physics.

## Notable For
- First documented invention in 1902 by Arthur Wehnelt
- Essential for controlling electron beam focus in thermionic devices
- Used in both vacuum tubes and early electron microscopes
- Known by multiple aliases, including Wehnelt cap and focusing cylinder
- Recognized in academic sources as early as 2013

## Body
### Invention and Purpose
The Wehnelt cylinder was invented in 1902 by Arthur Wehnelt, a German physicist. Its primary function is to control the focus and intensity of an electron beam within thermionic devices. By adjusting the electric field, it helps shape and direct the electron beam more precisely.

### Applications
The Wehnelt cylinder is a key component in the electron gun assembly of thermionic devices, including vacuum tubes and early electron microscopes. Its ability to modulate the electron beam makes it indispensable in these applications.

### Classification and Naming
As a subclass of the electrode, the Wehnelt cylinder serves as an electrical conductor in vacuum environments. It is named after its inventor, Arthur Wehnelt, and is also referred to by other names such as the Wehnelt cap or focusing cylinder.

### Historical Significance
The Wehnelt cylinder's invention in 1902 marked a significant milestone in the development of thermionic devices. Its inclusion in academic sources as early as 2013 underscores its enduring relevance in the field of electronics and physics.

## References

1. Freebase Data Dumps. 2013