AV Equipment and Connections – Part 5 – Passive vs. Active Adapters

06/01/16 by Brandon

Today begins the last stage of the A/V equipment and connections series. It is what I consider the most important part as we will discuss the dos and don’ts of connecting computers and monitors together through different ports.

We will go over these basic connections to determine when a passive or active adapter is needed. Let’s go through the different types that we will discuss during this part of the series:

  1. VGA computer output to HDMI monitor input
  2. USB computer output to HDMI monitor input
  3. DisplayPort computer output to HDMI monitor input
  4. USB stick directly into a USB monitor port
  5. HDMI computer output to DVI Monitor input

Let’s use number 1 as an example: the VGA computer output port to an HDMI monitor input port.


Active Adapter

I see this all the time on show floors right now. Everyone has their older company issued laptops and they rent or buy a new lightweight LED or LCD monitor. On the show floor, they discover that the monitor does not have a 14 pin VGA connection, but does have an HDMI port. So they get a passive adapter that changes the VGA connection to fit the HDMI port, only to realize that it did nothing to help the signal compatibility issue. Bottom line – it did not work. Why not, you ask?

Well, In order to answer that question we need to understand the difference between a passive adapter and an active adapter. Active adapters are also known as converters. In a nutshell, a passive adapter only changes the physical connection of the port to fit a different cable (or you could say it changes the cable to fit a different port). It would be like taking an American made electric hair dryer to England, and just adding an adapter on the end of the plug so it will fit into a British wall socket. You solved the connection problem, but not the electrical compatibility problem. Your 110V hairdryer was not compatible with the 220V British electrical system. Without a way to convert the voltage your hair dryer is toast. An active adapter would “convert the voltage.” If we put this back into A/V connection terms – an active adapter would convert the VGA analog signal to a digital HDMI signal. So the take-a-way from today’s topic is that the type of signal being transferred will determine the need for a passive or active adapter connection.