I understand now that the sizing of a digital sensor somehow correlates with a video tube from back in the day. Until this moment, I didn't even know there was a correlation. I've been away! Lol
As I see it, a digital sensor that is 12.80 mm x 9.60 mm, and has been designated a 1" sensor, relates somehow to a 1" video tube. Very simply, if possible, what is that relationship? Similarities in information processing capability?
I also scanned Wikipedia, and saw that the CCD sensor format came into being in the early '70s, following the demise of video tubes. So they've been around quite a while. Are they obsolete, if you compare them to the latest sensor formats?

A larger sensor in terms of the number of pixels yields a larger print of museum quality. A larger sensor size in terms of the physical size of the sensor changes the field of vision of a given lens - if the diagonal of a sensor is twice as long as another sensor, the larger sensor will have twice the field of vision for a given lens. Practically, this means a 100-400 mm lens on a 1 inch sensor ( 24 X 36 mm) will act like a 160 - 640 mm lens on an 15 X 23 mm sensor.

A larger sensor in terms of larger physical area for each pixel yields a higher quality electronic function. the larger size pixel will have a higher signal to noise level which results in crisper, clearer pictures especially in darker areas of a photograph.

Here is a link to sensor overall size:
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=imgres&cd=&cad=rja&uact=8&ved=0ahUKEwic4-OJtfvUAhXE4SYKHVK-A-8QjRwIBw&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAPS-C&psig=AFQjCNGfkE3SGbVbo6QM3v-ouqEDND3jdw&ust=1499662708255896

The pixel size will be the total area of the sensor divided by the number of pixels in the sensor. My Canon T6i APS-c sensor (22.2mm X 14.8mm) has ~24 Million pixels, and a pixel size of 3.72µm square. The 5D IV has a full size sensor with 30 Million Pixels yet has a pixel size of 5.3 µm square or over twice the area of the pixels in my camera. That should work out to about four times the signal to noise ratio on the big sensor. ( of course, the 5D IV is about 4-6 times the price of the T6i too.

It does if you want a camera you can fit in a pocket. I own a Nikon D810, but it isn't suitable to carry it everywhere I go. I'm sorry to say that. It takes beautiful pictures. It's just too large, bulky and conspicuous (where there is a risk of theft) for some casual sightseeing with family members. I looked at alternatives very carefully. The pocket requirement (mine) ruled out many fine cameras with larger sensors, either because of interchangeable lenses sticking out or viewfinders sticking up. I bought a Canon G7X Mark II. I have no complaints.

Sensor size also equates to camera size. If you want something to put in your pocket, you probably won't get anything larger than a 1" sensor. The lenses for cameras with larger sensors tend to be larger as well. Full frame cameras (24x36mm or close) tend to be large, and the lenses even larger. What are you willing to carry around, and to some extent, how much are you willing to spend for "better" pictures? Of course, they're better under scrutiny, but I've seen pictures taken with smaller cameras that are fantastic, including Micro 4/3. (Check out the Olympus models.)

This will no doubt be a very elementary subject for most of you, but I'm just learning and need a little help with details. I'll be asking a lot of questions in the future so please bear with me if you don't mind.
How is the numbering, used to identify a sensor's size, interpreted? For example: 1/2.3" (6.17 x 4.55 mm), 2/3" (8.80 x 6.60 mm), 1" (12.80 x 9.60 mm) etc. etc. I can see that the measurements in brackets, in millimeters, is the actual length by width size of the sensor. But how do you read, and interpret, 1/2.3", 2/3", 1" etc., and how do those numbers equate to anything?
Also, it would appear that the bigger the sensor, the better the photo. So, based on that premise, would that be a major factor to consider when purchasing a camera? If you purchase a camera that is going to max out your camera budget, should you opt for the one with the biggest sensor? And are there combinations of features, that you can apply to a camera, that would compensate for a lack of sensor size, and even create a camera that would produce higher quality photos, using a smaller sensor?

Any details would help.......Thanks.....Dave

Without getting scientific, here's how I understand this topic:
Light is the most essential ingredient of all images.There should be no question that a larger sensor contains more pixels than a smaller sensor. With more pixels, the sensor is physically capable of collecting more units of light (photons). With more light, you get a better image.

So why do we see such superb image quality with the smaller crop, MFT or iPhone sensors?

Why are there some smaller sensor cameras that have now earned "professional" status (e.g. Nikon D500) due to their superb performance in low light conditions?

One answer, IMO, is the technological advances of the specific camera and in particular how efficiently the pixels absorb and process the amount and quality of light that enters through the lens. Thus, sensor technology has been able to prove once again, the truism that "less is more". Sometimes...

Add to the improvements in sensor technology yet other advances and improvements such as in body and in lens image stabilization, lens quality, auto focus, etc., and we have lots of material for lively and stimulating discussion within our UHH family. But none of the advances can replace the fundamental elements of the exposure triangle, all of which address and affect one subject: light the quintessential ingredient of photography.
So, the more things change, the more they stay the same.

BJW

This will no doubt be a very elementary subject for most of you, but I'm just learning and need a little help with details. I'll be asking a lot of questions in the future so please bear with me if you don't mind.
How is the numbering, used to identify a sensor's size, interpreted? For example: 1/2.3" (6.17 x 4.55 mm), 2/3" (8.80 x 6.60 mm), 1" (12.80 x 9.60 mm) etc. etc. I can see that the measurements in brackets, in millimeters, is the actual length by width size of the sensor. But how do you read, and interpret, 1/2.3", 2/3", 1" etc., and how do those numbers equate to anything?
Also, it would appear that the bigger the sensor, the better the photo. So, based on that premise, would that be a major factor to consider when purchasing a camera? If you purchase a camera that is going to max out your camera budget, should you opt for the one with the biggest sensor? And are there combinations of features, that you can apply to a camera, that would compensate for a lack of sensor size, and even create a camera that would produce higher quality photos, using a smaller sensor?

Any details would help.......Thanks.....Dave