WEBVTT

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Do you remember when it seemed like every motherboard RAM module and adapter card out there was green?

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Well, these days they often come in other colors to be more aesthetically pleasing,

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with black being the most common. But even now, many circuit boards across a wide

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variety of electronics retain that classic green color. But why is green so prevalent?

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It certainly isn't because these big electronic companies are secret environmentalists.

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So what's the real reason? Well, there's actually not a single reason that everyone agrees on.

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But one major contributor is a layer on the PCB called the solder mask. As the name might imply,

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solder mask is a lacquer that protects the board against oxidation. Very important for electronics,

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as well as prevents different pieces of solder from accidentally touching each other and causing a

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ShortCircuit. Some of the materials used in solder mask, especially in the early days of

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electronics manufacturing, had a natural green hue to them since they contained glass epoxy.

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And you need only look at an old coke bottle to see that glass often has a bit of a green tint.

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At some point, though, manufacturers started to augment this natural green with green dye.

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One reason is that despite the glass epoxy, PCBs still had a rather unappealing brown color,

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even though they made numerous attempts to recolor the board. Through trial and error, though,

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they were able to turn the board into a less offensive shade of green that wasn't so god-awful

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to look at. But of course, people showing off exposed PCBs is a relatively recent phenomenon.

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Before the era of glass and acrylic computer cases, most people who stared at circuit boards

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for long periods of time were hobbyists, engineers, and quality control workers who needed to see

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the individual traces clearly. A green background provides a strong contrast for the gold and copper

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traces, as well as for the text that labels individual components, which is usually white

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to reduce mistakes and catch production errors before they make their way to consumers.

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Green is also a color our eyes are relatively sensitive to, but doesn't tend to be fatiguing

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over long periods of time the way yellow and red can be, which matters for professionals who stare

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at PCBs all day. There's a related argument that green boards also have higher yields,

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meaning they experience fewer errors in production. Conversely, this has also been floated as a reason

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why white PCBs are harder to find. The materials used in green solder mask actually allowed board

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components to be spaced closer together than some other colors, reducing errors on densely packed

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PCBs. Another popular hypothesis is that the US military had their hands on making the PCBs green.

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Obviously, militaries around the world have long favored green for its ability to camouflage

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soldiers and equipment, but it turns out that the American military actually had multiple patents on

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PCBs back in the early days of electronics. And of course, it would make sense that if soldiers

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were lugging electronics around in the field, it would be far better to blend into the rest of

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their equipment, and thus their environment, than, you know, some shade of orange that would

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effectively serve as a bullseye for an enemy sniper. But regardless of which of these reasons

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was the primary driver of green becoming an industry standard, the ubiquity of the green

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circuit board has also led it to become an inexpensive option since green PCBs can be produced

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in bulk further contributing to its popularity. Of course, manufacturing has improved over time,

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and nowadays it isn't too hard to order a PCB in a different color. And if we're talking mother

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boards, I mean, good luck even finding a green one anymore if you're trying to build your own

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computer. I guess you could always throw some fake plants inside your case and turn it into an

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AirSets terrarium if you really miss green. Thanks for watching guys. Like, dislike,

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check out some of our other videos like our recent video on chip stacking,

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