Why can't I connect my laptop to a TV using a VGA cable?

Answer: Many older laptops include a VGA output port that allows you to connect your computer to an external display. While many computer monitors have VGA ports, most televisions do not. Instead, TVs typically have composite, component, or HDMI video inputs. If your TV does not have a VGA port, you will need an adapter to output a VGA signal to your TV.

The most basic option is a VGA to composite adapter. This converts the VGA output to a standard composite video signal, which can be connected to the yellow RCA jack on the back of the TV. (You will still need a separate cable for the audio ouput, which connects to the white and red RCA jacks, used for left and right audio input.) If your TV has S-video or component video inputs, you can use a VGA to S-video or VGA to component adapter instead. All of these adapters are analog to analog converters.

If your TV has HDMI inputs, which are common on modern TVs, you can use a VGA to HDMI adapter. This converts the analog video output from the VGA port into a digital signal that can be transmitted to the TV's HDMI port. This type of analog to digital converter (ADC) is more advanced than a basic analog to analog converter, but they are still pretty inexpensive.

While there are many different types of VGA adapters available, if you use the VGA connector on your laptop, the maximum resolution may be less than if you used a digital output port, such as DVI or HDMI. Additionally, an analog video signal may not be as clear as a digital one. Therefore, it's best to use a digital connection (such as HDMI to HDMI) whenever possible.

Published: May 28, 2014 — by Per Christensson