VGA Splitters Explained – Active or Passive?
October 15, 2009 by Victor
What is a VGA Splitter?
A VGA splitter is a device that duplicates a VGA signal. In other words, in accepts one VGA input, and clones it to multiple VGA outputs.
VGA Splitters and Screen Capture
VGA Splitters are often used in screen capture solutions where a VGA signal needs to be captured. Since a VGA splitter clones a single VGA signal into two or more feeds, this allows the user to retain the use of a standard computer monitor, while at the same time sending the VGA signal to a capture device like a frame grabber.
Active and Passive VGA Splitters
Two different types of VGA splitters exist. Active VGA splitters and passive VGA splitters. Passive VGA splitters, pictured below, are also known as simply Y-splitters or Y-adapters:
Active VGA splitters, on the other hand, consist of hardware devices that need to be powered to operate and often have more than 2 ports on the output side. A VGA Splitter from Kramer Electronics is shown below:
When to use a Passive Splitter
A passive splitter has only a few advantages over its active counterpart. Firstly, passive splitters are extremely cheap in price, as they can often be found for under $10. Secondly, they are compact and require no power source.
Unfortunately, passive splitters also have some downfalls. They are not compatible with all equipment, as passive splitters don’t let monitors properly identify themselves to the VGA source. Passive splitters support a maximum of only two outputs and, since there is no amplification of the signal, the outputs are often of inferior quality than if seen without the splitter.
It is suggested to use a passive splitter when you are connecting two of the same model monitor to the splitter’s output, no power source is available, or when picture quality is unimportant to you.
When to use an Active Splitter
Active VGA splitters have countless advantages over passive VGA splitters. Active VGA splitters can clone one VGA port into virtually any number of outputs. Furthermore, an active VGA splitter identifies itself to the computer as a monitor, meaning that there will be no incompatibility issues with the different models of monitors and VGA-based equipment connected to it.
Furthermore, active VGA splitters slightly amplify the signal (not to be confused with VGA amplifiers) which means that the resulting VGA output will be of significantly superior quality when comparing to that of a passive or Y-splitter.
Realistically, the one and only disadvantage of an active splitter is that it requires a power source for it to operate.
If possible, using an active splitter is recommended for all applications. However, since proper active splitters retail for well over the $100 mark, a passive splitter will sometimes suffice.
When choosing an active VGA splitter, always make sure to check its specifications in order to see if it is compatible with the resolution you plan to use it with.