A Lot Of Transistors
 

I just read that the new Apple Xs iPhone contains 6.9 billion transistors. I got to thinking. Could that 6.9 billion transistors be greater than all of the vacuum tubes ever produced?

Curious minds want to know.....

Well one can look at early to mid 60's estimates of all the radios sold in the USA (the number of transistor sets made before then is probably comparable to the number of tube sets made after), then multiply that by at least 5 (most of those sets were AA5s most of the rest were higher tube count).

Something similar could be done for TVs using ~1970 as the total sets sold point since most SS sets came out 1968 and later, and most tube sets were done by 1975. And something like 25 for an average tube count.

You'd have also have to factor in HiFi amps, phonographs, tape/wire recorders, computers (yes there were tube based computers), broadcast and industrial (such as telephone co) tube equipment, as well as replacement tubes for all such equipment...Also, CRTs and the microwave source in all microwave ovens (not to mention microwave RF communication systems) count as vacuum tubes too...And I'm probably forgetting other things like Photomultiplier tubes.

This is the kind of sanity check problem we liked to give to potential engineering hires. Not to see if they knew the answer, but to see how they'd approach a sane estimate.

so let's talk orders of magnitude. I'd say the peak tube color TV unit sales were about 10 million per year, and each had about 25 tubes, so thats 250 million tubes per year. If we guess that TV sets were the major use of tubes, lets just use that number as the total produced. Then it would take about 28 years of peak production to equal 7 billion. So, since tube TVs were not produced at peak level for 28 years, the total tubes is less than 7 billion. Throw in some factor for other uses (maybe 2 times), and it would take 14 years of peak production. This is getting to be order-of-magnitude the same as the peak years of tube color TV (maybe 5 years total). So, the estimate of tube production is on the order of 7 billion, but maybe smaller by a factor of 2 to 4 (or 8?).

Feel free to refine this if you want!

Edit: The point is, you can be fairly sure it's neither as low as 700 million nor as high as 70 billion.

Edit #2: I'm going to double the estimate to include tubes for B&W TV made over the years. Still in the same order of magnitude.

Also there were a lot of foreign makers/markets too, and you can bet most figures from the USA ignored foreign electronics production, or had incomplete data.