It seems every day our technology is getting more efficient and also smaller. Paradoxically, the smaller computer chips get, the more capable they are at functioning and storing data. Yet the co-founder of Intel, Gordon Moore, posited in 1965 that the number of transistors in a circuit board would double every two years. This is now known as Moore’s law, and it’s proven to be eerily accurate.

The giant supercomputers of the 1970s and 80s that would rival a couch in terms of size are less powerful than the small handy devices we carry with us every day. In just a few decades we’ve been able to harness incredible amounts of computing power in tiny spaces, and this exponential trend doesn’t seem to have an end. Though some researchers believe the end of this law lies in an atom-sized transistor.

But rather than get too bogged down in the scientific jargon of micro-chips, let’s take a look at a few interesting things about printed circuit boards (PCBs) that you may not know.

1) Why Less is More in Processing

Size has often been directly correlated with power. The larger an army, the bigger the muscle, the heavier the weight, the more power. But the opposite is true in processing power. Printed circuit boards feature several transistors which must interact with one another by sending and receiving electrical impulses. The farther apart these receptors, the longer it takes for the signal to get there. By shrinking the size of the chip, this distance between transistors is also decreased. Less electricity is needed to send the same signal, and this signal is sent and received faster. Therefore, the smaller the chip, the more efficient it is.

Of course, making these spaces smaller wasn’t always possible. In the mid-20th century when scientists were beginning to develop computers, they had to manufacture all the components manually. As a result, original computers were massive, taking up the space of entire room or more to do even the simplest of equations. Back then, this was of course a major feat. Today, our smartphones make original computers seem laughable, wasteful, and unnecessarily bulky.

2) How Processors Got Smaller

Human ingenuity has made printed circuit board assembly easier and cheeper than ever before. As stated before, in the past circuit boards had to be assembled manually, meaning they had to be bigger and therefore took longer and cost more to manufacture. Human motor skills and eyesight can only go so far, after all. Today, circuit boards are first designed using PCB design software. The designer can first lay out the orientation and size of the circuit board on the software, allowing for spaces between transistors as small as 0.04 inches (1 mm) or smaller.

Once the design is finalized, PCB manufacturing companies create a prototype and test it for use by printing the design via computer onto a template of the proper dimensions. If the prototype assembly is successful, the design can be mass produced for a relatively low cost and sent to the market. Gone are the days of manual assembly and gigantic computers.

3) The Development of PCB Inspection

It’s important for PCB manufacturers to ensure their chips are working properly. In the past, the only way for people to inspect their circuit boards was to do so manually. However, this takes a bit of time and therefore can become costly. Additionally, most chips have become too small and detailed to be properly inspected by the human eye. Today there are two more kinds of PCB inspection to account for this.

AOI PCB inspection stands for automated optical inspection. As the name implies, it refers to a method of PCB inspection that utilizes optical software superior to the human eye to compare two images and detect any flaws. However, some chips are becoming so small that even optical software has a hard time detecting errors. This is where AXI (Automated X-Ray) PCB inspection comes in. AXI PCB inspection can see under and through chips to get a better look at otherwise invisible solder joints.

Now you may have a better idea of how and why your smartphone is able to do so much. Moore’s law seems to indicate that in another decade we might barely be able to see those chips at all.