I’m sure you’ve heard of the term “transistor(s)” at a certain point in your life. Well, they are the building blocks behind the technology we rely on every day — computers, calculators, cameras, and cars. So, What is a transistor?

#1 Counting Systems

At the core of a computer’s operation lies the binary system… 0’s and 1’s.

Just like the base ten positional system and tally marks, binary is a system of counting.

In the base ten counting system, we think of counting with digits from 0 to 9, adding a new digit after every ten.

0 (1 digit)

11 (2 digits)

123 (3 digits)

and so on…

Each digit added ultimately represents an increase in power of ten.

Tally marks, although another system of counting, proves to be highly inefficient. A new tally is added to denote an increment of 1.

Binary is very similar to the base ten positional system; however, numbers are represented by only using 0’s and 1's.

Here’s what it looks like when a computer counts to ten: 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 1010.

So why do computers use binary instead of the base ten positional system?

Well, it comes down to the physical limitations of computers. Binary is much easier to implement into electronic circuits than other counting systems.

#2 Transistors

In essence, transistors are very tiny switches capable of being turned on or off by an electrical zap. To enable computers to count efficiently, we employ the binary system, where each switch represents a binary digit: 0 (off) or 1 (on).

If computers used tally marks, eight transistors turned on would only count up to 8, which is very inefficient. However, with binary, if all eight transistors were on, the count would reach up to 255 - marking a much more efficient counting system.

It is important to note that a single transistor is referred to as a “bit”, and a “byte” is 8 of these transistors in sequence.

So, a byte (8 transistors) can represent any number between 0 and 255.

#3 ASCII

Now we have a fundamental understanding of how transistors are used by computers to understand numbers… what about, colors (such as the color of the pixel on your screen), letters, and special characters?

This capability is made possible through ASCII, an acronym for the American Standard Code for Information Interchange — a character encoding standard for electronic communication.

ASCII serves as a bridge between a computer’s binary data (0’s and 1’s) and the letters and symbols comprehensible to humans (A, b, C, +, and so on). Each value represented by a byte (eight transistors) is assigned a corresponding character by ASCII.

You might be thinking, “Doesn’t it take eight transistors to represent a single character? So, a 100-character sentence would require around 800 transistors!” Indeed, you’re correct. You may have come across terms like 16-bit and 8-bit programs. As eight transistors can only count up to 255, which is insufficient for the extensive calculations computers perform, the concept of 16-bit arose.

Modern computers are designed to recognize two bytes as a single number. Consequently, two lines of transistors, totaling 16 transistors or 16 binary digits, can count up to 65,535, surpassing the limitations of 255. Additionally, there are 32-bit and 64-bit systems, each with increased capacity. The crux of the matter is that computers comprehend and operate on binary, which represents letters, numbers, special characters, color codes… and so on through ASCII.

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It’s worth noting that the microchips powering our computers are home to billions of these simple and tiny transistors. Like highlighted by Moore’s Law, we continue to pack more and more of these powerful little components into smaller spaces, driving the exponential growth of computing power (2x transistor count each year!).