RCA cables, also known as phono connectors or cinch connectors, are a type of analog audio/video cable that is commonly used to connect components in home stereo and home theater systems. The cables have a distinct round connector on each end that consists of a metal tip surrounded by a metal ring. RCA cables transmit stereo audio in left and right channels using white and red connectors, and transmit video using yellow connectors. Additional colors like black, blue, green etc. are also used for non-standard signals.
The yellow and green RCA cables specifically are used for video and RGB signals respectively. While they appear similar, there are some key differences between the two in terms of their applications and signal transmission:
Yellow RCA Cable
- Used for composite video signals
- Carries video on a single shared channel
- Lower video quality than component video
- Commonly used with older analog devices
Green RCA Cable
- Used for RGB analog component video signals
- Carries separated video for red, blue and green channels
- Higher video quality than composite video
- Commonly used with newer analog components
In this article, we’ll take a deeper look at how yellow and green RCA cables are used and compare their features and specifications in detail.
Applications
Yellow RCA Cable Uses
Here are some of the most common applications of a yellow RCA cable:
- Composite Video Connection – The yellow RCA cable carries a complete composite video signal over a single shared channel. This makes it suitable for connections between older analog video sources like VCRs, DVD players, camcorders etc. and displays like TVs.
- Component Video Connection – A yellow RCA cable can be paired with red and white RCA cables to transmit right and left analog audio channels along with the video signal. This forms a component video connection commonly used with devices prior to HDMI.
- Game Console AV Output – Older game consoles like the Nintendo Entertainment System (NES), Super Nintendo (SNES) and PlayStation 1 output composite video through a yellow RCA connector. This allows connection to a TV.
- CCTV Cameras – Analog CCTV surveillance cameras output composite video through BNC or RCA connectors. A yellow RCA cable can connect the camera to the display monitor.
- Video Projectors – Some older video projectors accept composite video input through RCA connectors. A yellow RCA cable can connect video sources like DVD players to the projector.
Green RCA Cable Uses
Here are some of the most common applications of a green RCA cable:
- Component Video Connection – The green RCA cable carries the green color channel in a component video connection. It needs to be paired with blue and red RCA cables to transmit the full component video signal.
- EDTV Connection – The green RCA cable can connect the Y (luminance) output from an enhanced definition television (EDTV) source to a display.
- HDTV Connection – Some older HDTVs split the component video output into separate RCA connectors instead of using a single YPbPr connector. The green cable carries the Y (luminance) channel.
- RGB Connection – The green RCA connector can be used for the green analog channel in an RGB connection between computers and displays. This requires a blue cable for blue and red cable for red.
- YC Separation – A green RCA cable can transmit the Y (luminance) signal after separating it from composite video through a comb filter. The C (chroma) signal is transmitted via the yellow cable.
Signal Transmission
Yellow RCA Cable Signal
A yellow RCA cable carries a composite video signal. This consists of the following parts combined into a single channel:
- Luminance signal (brightness/contrast information known as luma, Y or monochrome)
- Chrominance signal (color information known as chroma, C or Pb/Pr)
- Synchronization signals (horizontal sync and vertical sync)
By combining all the video information into one signal, composite video cables like the yellow RCA can get by with a single connector for both audio and video. However, mixing everything into one channel limits the maximum video quality due to crosstalk between luma and chroma channels. Composite video is standard definition and limited to a total bandwidth of 6 MHz for the shared signal.
Green RCA Cable Signal
A green RCA cable carries the green analog video channel in a component video signal. This consists of the following independent channels:
- Y – Luminance signal (brightness)
- Pb – Blue color difference signal
- Pr – Red color difference signal
By separating the luminance and color channels, component video eliminates crosstalk and provides higher video quality. The green cable carries the Y luminance channel, while the blue and red cables carry the Pb and Pr channels respectively. Each channel has a wider bandwidth since they are not combined, allowing for HD resolutions. Component video cables like the green RCA provide better quality than composite yellow RCA cables.
Video Quality Comparison
| Video Signal Type | Maximum Resolution | Pros | Cons |
|---|---|---|---|
| Composite Video (Yellow RCA) | 480i |
|
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| Component Video (Green RCA) | 1080p |
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As seen above, component video allows for significantly higher maximum resolutions like 1080p HDTV due to its separation of luma and chroma channels. Composite video is limited to standard definition 480i resolution. Component cables like the green RCA provide a major boost in picture quality over composite yellow RCA cables.
Cable Specifications
While both yellow and green RCA cables look identical, there are some important internal physical differences between the two:
Impedance
- Yellow RCA Cable: 75 ohms impedance
- Green RCA Cable: 75 ohms impedance
The impedance needs to match the output impedance of the source device and the input impedance of the display device, normally 75 ohms for consumer analog video connections. Both yellow and green RCA cables use the same 75 ohm standard impedance.
Shielding
- Yellow RCA Cable: Basic single braid or foil shielding
- Green RCA Cable: Double or triple shielding recommended
Since the green cable carries very high frequency luminance video, premium quality cables will provide extra shielding to prevent signal degradation and interference. The basic shielding on composite yellow cables is generally sufficient since the signal frequencies are much lower in resolution.
Cable Grade
- Yellow RCA Cable: Standard RG-59 or RG-6 cable
- Green RCA Cable: High-grade RG-6 cable recommended
RG-6 grade coaxial copper cable provides the best quality for green RCA cables carrying HD video signals. Composite video only requires standard RG-59 cable. Using high quality, well shielded cabling helps maintain signal integrity.
Connectors
- Yellow RCA Cable: Nickel or gold plated connectors
- Green RCA Cable: Gold plated connectors recommended
Gold plated connectors prevent corrosion and improve conductivity, providing the cleanest signal transfer. They are recommended for the high frequency green cables, while basic nickel connectors are generally sufficient for yellow composite video cables.
Audio Signal Transmission
In addition to video transmission, RCA cables like yellow and green are also capable of carrying analog stereo audio signals when used in component video connections:
- White RCA Cable: Left audio channel
- Red RCA Cable: Right audio channel
The audio signals have a much lower frequency than video, so basic copper core cabling is sufficient. However, gold plated connectors help maintain clean audio quality for sensitive audio equipment connections.
Conversion Between Yellow and Green Cables
Since yellow RCA cables carry composite video and green cables carry component video, the signals they transmit are not directly compatible. However, conversion between the two is possible with external devices:
Composite to Component Conversion
A composite to component converter takes the combined composite video signal from a yellow RCA cable as input. It then separates and outputs the luminance (Y) and color difference (Pb/Pr) signals needed for component video over green, blue and red RCA cables.
Component to Composite Conversion
A component to composite converter takes the Y, Pb and Pr component signals from separate green, blue and red RCA inputs. It combines them into a single composite video signal output over a single yellow RCA cable.
This conversion allows adapting between component and composite analog video standards, enabling connectivity between otherwise incompatible yellow and green RCA cables.
Obtaining Yellow and Green RCA Cables
Here are some options for acquiring new yellow and green RCA cables to connect analog home theater components:
- Electronics stores – Stores like Best Buy often stock various lengths of basic yellow and green RCA audio/video cables.
- Online Retailers – Amazon and Monoprice offer affordable yellow and green RCA cables in bulk lengths up to 100 ft.
- Cable Manufacturers – Companies like Mediabridge and Blue Jeans Cable provide high quality premium yellow and green RCA cables.
- Audio Video Installers – Custom AV installers can make or provide proprietary thick gauge RCA cables for in-wall installations.
When purchasing green RCA cables, look for features like triple shielding and gold plated connectors to ensure maximum video quality for HD signals. Basic yellow RCA cables are sufficient for most composite video applications.
Conclusion
In summary, while yellow and green RCA connectors appear identical, they serve very different analog video signal transmission needs. Yellow RCA cables carry composite video over a single shared channel and are limited to standard definition signals. Green RCA cables transmit the luminance video in component connections, providing full HD resolution with minimal crosstalk when paired with blue and red cables. Understanding these key differences allows you to best match cables to the analog audio/video devices in your home theater setup.
