# carbon microphone

> type of microphone design

**Wikidata**: [Q1482299](https://www.wikidata.org/wiki/Q1482299)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Carbon_microphone)  
**Source**: https://4ort.xyz/entity/carbon-microphone

## Summary
A carbon microphone is a type of microphone design that uses carbon granules to convert sound vibrations into electrical signals. It was one of the earliest practical microphones and played a crucial role in early telephone and radio technology.

## Key Facts
- Carbon microphones are a subclass of microphones, which are acoustic-to-electric transducers that convert sound into electrical signals
- The carbon microphone has a GND identifier of 4779833-6
- It has a Lexeme ID "kulkornsmikrofon" (Norwegian for carbon microphone)
- It has an IEC 60050 (IEV) number of 801-26-12
- Carbon microphones have multiple Wikipedia articles across languages including English, German, Spanish, Dutch, and others
- The technology is represented in museum collections with museum_digital_tag_id of 96644
- Freebase ID for carbon microphone is /m/0d9fkw
- It has an ELHuyar ZTH ID of 135033
- The carbon microphone has a sitelink count of 23

## FAQs
### Q: How does a carbon microphone work?
A: A carbon microphone works by using carbon granules that change resistance when compressed by sound waves. These variations in resistance create corresponding electrical signals that mirror the original sound vibrations.

### Q: When was the carbon microphone invented?
A: The carbon microphone was invented in the late 19th century, with Thomas Edison developing a version for telephone use in 1877, though earlier carbon-based microphones had been explored by others.

### Q: What are the primary applications of carbon microphones?
A: Carbon microphones were primarily used in early telephone systems, public address systems, and early radio broadcasting. They've largely been replaced by more sensitive and clearer technologies like dynamic or condenser microphones.

### Q: How does a carbon microphone compare to modern microphone technologies?
A: Compared to modern microphones, carbon microphones are generally less sensitive and produce lower quality audio. However, they have a unique character and were historically significant due to their robustness and ability to amplify signals without additional power.

## Why It Matters
Carbon microphones represent a critical milestone in audio technology history. As one of the first practical methods of converting sound to electrical signals, they enabled the development of early telephone communication systems, which revolutionized long-distance communication. The carbon microphone's ability to amplify weak electrical signals without external power made it particularly valuable in early telecommunications and broadcasting systems. Despite being largely superseded by more advanced technologies, the carbon microphone's fundamental principles of variable resistance influenced subsequent microphone designs and helped establish the foundation for modern audio engineering. Its historical significance in telecommunications technology cannot be overstated, as it played a pivotal role in connecting people across distances in the early days of electronic communication.

## Notable For
- Being one of the earliest practical microphone designs that enabled reliable telephone communication
- Using carbon granules to convert sound vibrations into electrical signals through variable resistance
- Its ability to amplify electrical signals without requiring additional power
- Playing a pivotal role in early telecommunications systems and radio broadcasting
- Having a unique sonic characteristic that has been sought after in certain audio applications despite technological advancement

## Body
### Technical Principle
Carbon microphones operate on the principle of electrical resistance changes caused by pressure. They contain a capsule filled with carbon granules between two metal plates. When sound waves strike the diaphragm, it moves, compressing and decompressing the carbon granules. This compression changes the electrical resistance between the plates, creating an electrical signal that corresponds to the original sound.

### Historical Development
The carbon microphone was developed in the late 19th century with multiple inventors contributing to its evolution. The technology quickly became standard in telephone systems and early radio equipment due to its reliability and signal amplification capabilities.

### Construction and Components
A typical carbon microphone consists of:
- A diaphragm that responds to sound waves
- A chamber filled with carbon granules
- Two metal electrodes that apply pressure to the granules
- Housing that protects the internal components
- Connections to electrical circuits

The carbon granules are specially processed to provide consistent resistance changes and durability.

### Performance Characteristics
- Frequency response: Limited compared to modern microphones
- Sensitivity: Lower than modern microphone technologies
- Signal amplification: Inherent capability to amplify without additional power
- Durability: Robust construction with relatively simple mechanics
- Impedance: Typically higher than modern microphones

### Modern Applications
While largely replaced by more advanced technologies in professional audio, carbon microphones continue to be used in:
- Vintage telephone replicas
- Certain musical instruments for their unique tonal characteristics
- Educational demonstrations of basic electrical principles
- Niche audio applications where their specific sound characteristics are desired
- Historical reenactments and museum displays

The technology, though largely obsolete for general use, remains an important part of audio history and is studied for its fundamental principles in audio engineering.

## References

1. Freebase Data Dumps. 2013