# EM34

> magic eye tube

**Wikidata**: [Q1275143](https://www.wikidata.org/wiki/Q1275143)  
**Source**: https://4ort.xyz/entity/em34

## Summary
The EM34 is a specific model of magic eye tube, a type of vacuum tube used to provide a visual indication of electronic signal amplitude. Also known by the alias 6CD7, it complies with Mullard–Philips tube designations and operates using a luminophore and triode structure to display signal strength or tuning status in devices such as radio receivers.

## Key Facts
- **Entity Type**: Vacuum tube model (instance of magic eye tube).
- **Aliases**: 6CD7.
- **Design Standard**: Complies with Mullard–Philips tube designations.
- **Class Structure**: Contains a luminophore and triode structure for visual indication.
- **Parent Class Invention**: The magic eye tube was invented by Allen B. DuMont in 1932.
- **External Identifiers**: Radiomuseum ID `em34`; Google Knowledge Graph ID `/g/122d82qt`.
- **Documentation**: Described in English datasheets (frank.pocnet.net) and German technical archives (jogis-roehrenbude.de).
- **Visual Media**: Image available via Wikimedia Commons (`EM34-Ansicht.jpg`).
- **Commons Category**: EM34 (vacuum tube).

## FAQs
### Q: What is the primary function of the EM34?
A: The EM34 functions as a visual indicator for electronic signals, utilizing a luminophore and triode structure to display signal amplitude. It is commonly used to indicate tuning status or signal strength in electronic devices.

### Q: What designations or standards does the EM34 follow?
A: The tube complies with Mullard–Philips tube designations and is alternatively identified by the alias 6CD7.

### Q: Where can technical details and datasheets for the EM34 be found?
A: Technical details are archived in German on Jogis-Röhrenbude and available as English PDF datasheets on Frank's Electron Tube Pages (frank.pocnet.net).

### Q: How does the EM34 relate to the broader history of vacuum tubes?
A: The EM34 is a specific model within the "magic eye tube" class, a technology invented by Allen B. DuMont in 1932 to visually represent electronic signals in radios and tape recorders.

## Why It Matters
The EM34 serves as a concrete example of the "magic eye" technology that revolutionized user interaction with early electronics. As a vacuum tube model complying with Mullard–Philips standards, it represents the widespread adoption and standardization of visual tuning aids in radio receivers and tape recorders. By translating invisible electronic signal amplitude into a visual display through its luminophore and triode structure, the EM34 and similar models (like the EM80 and 1E4A) allowed users to precisely tune equipment and monitor recording levels, making it a significant component in the history of consumer audio and electronic display technology.

## Notable For
- Being a distinct model within the magic eye tube class, which pioneered visual signal indication.
- Compliance with the Mullard–Philips tube designation system.
- Having an alternative identifier (6CD7), indicating cross-manufacturer or system recognition.
- Serving as a primary example of electron-ray indicator tubes used in mid-20th century electronics.
- Providing the specific visual "magic eye" effect derived from Allen B. DuMont’s 1932 invention.

## Body
### Classification and Design
The EM34 is classified as a vacuum tube model and falls under the subclass of the "magic eye tube." It is designed to provide a visual indication of the amplitude of an electronic signal. Structurally, it employs a combination of a luminophore and a triode; the luminophore reacts to signals to create a visual display, while the triode manages the signal amplification.

This model complies with the Mullard–Philips tube designations, a standard system for identifying vacuum tubes. It is also referenced under the alias **6CD7**.

### Historical and Technological Context
The EM34 is a specific implementation of the magic eye tube technology invented by **Allen B. DuMont in 1932**. While the EM34 is a distinct model, it shares the core utility of the parent class: serving as a tuning indicator in radio receivers and tape recorders. It operates on the principle of displaying signal strength visually, allowing users to optimize device performance.

The magic eye tube family, which includes the EM34, the EM80, and the subminiature 1E4A (introduced in 1960), is culturally recognized under various aliases such as "electron-ray indicator tube," "Ojo magico" (Spanish), and "Волчий глаз" (Russian).

### Documentation and Resources
Technical and historical data regarding the EM34 is preserved across several specialized archives:
*   **Datasheets**: An English-language PDF datasheet is available from Frank's Electron Tube Pages (`frank.pocnet.net/sheets/030/e/EM34.pdf`).
*   **Technical Descriptions**: A detailed description in German is archived at Jogis-Röhrenbude (`jogis-roehrenbude.de`).
*   **Visual References**: The tube is documented visually in the Wikimedia Commons category "EM34 (vacuum tube)," with a specific image file available (`EM34-Ansicht.jpg`).

### Database Identifiers
The entity is tracked in several knowledge systems:
*   **Wikidata**: Described simply as a "magic eye tube" with 2 sitelinks (Wikimedia Commons and German Wikipedia).
*   **Google Knowledge Graph**: ID `/g/122d82qt`.
*   **Radiomuseum**: ID `em34`.