A few days ago I asked my wife what she thought was the most important invention of the last 100 years. Without pause, she responded “the credit card!”

I suppose that “important” is relative, but my answer is the transistor. As Wikipedia puts it, “The transistor is the fundamental building block of modern electronic devices, and its presence is ubiquitous in modern electronic systems.” Semiconductors are vital to everyday life because they have radically reduced the size, cost and power consumption of all modern electronics.

Life wouldn’t be the same without transistors (or without credit cards, admittedly). Your laptop would weigh hundreds of pounds and be a “mainframe” computer without transistors. Your television would rely on tubes, and you couldn’t mount it on the wall – it would weigh 100 pounds or so without transistors. No mobile phones, either – your telephone would have a rotary dial, and the handset would be connected with a wire. Telephone directories would still be printed books weighing 5 pounds or so.

Nothing wireless would exist – no Blackberrys, no iPhones, no iPods, no iPads, no portable mpg players, no handheld games. And although the internet would still exist, its use would probably be limited to national laboratories (as it was when it was invented by Bolt, Beranek and Newman a generation ago), and perhaps large corporations. When you plan a vacation, you would have to rely on printed guidebooks and travel agents. When you needed to do some research, or look up any simple fact, you’d head to the library. (The internet is leading to the demise of the local library, but that’s a subject for another day.) A VCR would be possible (though not CDs or DVDs), but they would be very expensive and you couldn’t program them to record your favorite program when you are out.

When driving, you would need to pull over to the side of the road to read your paper map because GPS devices wouldn’t exist. Airplane and naval guidance systems would still rely on mechanical devices based on astronomical observation. There would be no ATMs because you wouldn’t have a bank card with a magnetic stripe on the back to identify who you are – such systems would be too massive and too expensive to build and operate. If you were ill, your doctor couldn’t have a CAT scan or an MRI performed. Your car wouldn’t have an anti-lock brake system or on-board diagnostics or any other modern electronics-based on-board systems.

Your camera would still rely on film, and it would be slow and expensive to share your pictures. You would have to make a phone call or write a letter to stay in touch with your friends and family because email wouldn’t be available at home and there would be no such thing as internet-based “social media”. (Some people I know think that that would be a good thing, but I don’t.)

The pace of invention would be far slower. Yes, it would be easier to stay current, but that’s because there would be less to keep up with. Product design and all other forms of engineering would be slower and more expensive because scientists, engineers and students would be doing math by hand or using an abacus – they wouldn’t have access to software like Maple and MapleSim. (The marketing guys always like me to tie my blogs back to our company…)

Manufacturing would be slower, less reliable and more costly because manufacturing control systems and other highly automated processes wouldn’t exist. “Just in time” manufacturing, “supply chain management”, automated inventory management and many other aspects of modern production simply wouldn’t exist. The quality, uniformity and reliability of most goods would be lower. Customers would have to call vendors to inquire about the shipment status of the things they purchased. Supermarket check-out lines would be longer because bar coding wouldn’t exist, and there would be no self-checkout lines. And while the software industry pre-dates the transistor, it would not have experienced the explosive growth that it has enjoyed. The consumer software industry simply would not exist.

Invention of the transistor is commonly credited to Bell Laboratories in 1947, but its history actually dates back to a patent filed by Canadian physicist Julius Edgar Lilenfeld in 1925. (Most of you would probably be amazed at the list of technology “firsts” that have come from Canada.)

The first silicon transistor was produced by Texas Instruments in 1954. William Shockley, the Solid State Physics Group leader at Bell Labs, greatly expanded the knowledge of semiconductors and is often referred to as the “father of the transistor”. In fact, the Bell Labs team modified the common saying that “nature abhors a vacuum” into “nature abhors a vacuum tube”. The term “semiconductor” was coined by John Pierce.

Julius Edgar Lilenfeld	William Shockley	John Pierce

It’s an interesting thought exercise to ponder what the most important invention of the coming century will be. Of course, if I knew that I’d change careers and become a very wealthy investor. Speaking of investors, there would be no such thing as “on-line trading”. You would have to rely on a professional trader, and if you wanted to be one yourself you’d have to make it your full-time occupation and you’d rely on a “stock ticker” machine. And if you think that would be better or safer, remember the stock market crash of 1929.