Circuit boards are vital for keeping many of the gadgets that we use in our everyday lives running. From our computers to cell phones to microwaves and even digital clocks, printed circuit boards (commonly abbreviated as PCB’s) are everywhere. Of course, different items require different kinds of printed circuit boards that might have different layouts, materials, and assemblies. There are also advantages to the various types of printed circuit boards in circulation, depending on their application. The methodology for creating PCB’s began early in the 20th century, but was refined during WWII. As technology has continued to be refined, so too have printed circuit boards; multilayer circuit boards, for example, became more commonly used in the 1990s. We’ll discuss the major types of circuit boards, common construction processes, and advantages to the different types of printed circuit boards.
What are Circuit Boards and How are They Used?
Circuit boards are thin sheets that have a surface coated in metal. The sheets themselves are usually composed of some kind of insulating material. The metal is then etched, so that electricity can travel through the etching and around different elements that are soldered onto the sheet. Usually this metal is copper, which helps conduct electricity to connect two points of the printed circuit board. Essentially, the aim of circuit boards is to make connecting different pieces much easier and less expensive.
Our electronics couldn’t be as small as they are today without the printed circuit board. These boards have allowed electronic circuits to shrink and all be found in the same place: a durable, compact board. Some circuit boards also have holes, which means that other components like resistors can be be inserted as well, giving the circuit board even more function.
Generally, a board will be anywhere from two to four layers, with drill holes under 10 mils in diameter and five mils for air gaps and trace widths. They’re 0.062 inches thick with a copper foil weight of one ounce and standard FR-4.
What are the Major Types of Circuit Boards and How are They Constructed?
There are both rigid and flexible printed circuit boards, thanks to the Auto-Sembly process that dates back to the mid-1950s, courtesy of the United States Army. The most basic of these printed circuit boards is the one layer printed circuit board or one layer PCB. They contain copper tracks or only interconnect on one surface. However, there are also double-sided PCB’s and multi-layered PCB’s — the more layered the circuit board, often the more complicated it is.
Construction-wise, there are two main types of construction processes used to make the printed circuit boards. One is through the hole and the other is surface mount construction. PCB’s constructed via the surface mount method are up to one tenth of the size of through-hole circuits, which can be helpful if you have a particularly complicated circuit board you’re working with. For simpler boards, the through-hole construction would work just fine.
What are the Advantages to Using Different Kinds of Circuit Boards?
Single-sided PCB’s, as we discussed, are the simplest type of circuit board, and good for easy electronics. They’re also cheap to produce. Double-sided PCB’s have a wider range in their application and circuits can be connected either using through-hole or surface mounting construction. Multilayer PCB’s allow designers to create thick and compound designs, which makes them more complex and intricate in their application.
Rigid PCB’s are often found in things like computer hard drives or your cell phone — the board won’t twist or bend, unlike flex PCB’s. Flex PCB’s can be useful in spaces where weight matters or where space is limited and can be single or double sided, or have multiple layers.
As you can see, each type of circuit board has its own unique set of advantages and applications, depending on what the designer needs.
We have printed circuit boards to thank for much of the technology we use on a daily basis. Though small, they’re mighty, and help power businesses, keep us connected, and moving forward.