Why 0805?

Bear with me here...

01005 (teeny - I've seen them)
0201
0402
0603
0805
1005
1206 (big)

Does this bother anyone else? In a perfect world, wouldn't the 0805 size be reasonable and follow the 2x1 sizing pattern and be 0804?

Maybe I've been routing too long today. I think I still have some narcotic cough syrup left now that I think about it.

Well 805 is my favourite size as it easily fits between tracks on veroboard.

I see your point though.

Well, I was bored and couldn't find the answer. So, I made a list of sizes using both inch and metric numbers:



There are some sizes for which I did not have the metric/inch equivalents. I don't believe they are necessary to understand my hypotheses.

First, the 2:1 ratio may be an artifact of sampling. Although a lot of sizes fit that pattern, a lot do not fit it.

Second, a hypothetical "804" converted to metric would be a 2010. Since the 2010 is a recognized inch size, it may have been decided to avoid potential confusion and make it an 805, which in metric is a 2012.

Third, things just happen, and the engineers weren't even thinking about the apparent pattern in aspect ratios at the time.

John

PS: I can't get the table to post. See the attachment.

speakerguy79 said:

Does this bother anyone else?

Click to expand...

Yes. I was blissfully happy until you pointed this out. Now I can't sleep.