The circle-of-5ths is a feature of all equal-temperaments which have an interval whose size is in the vicinity of the 3:2 ratio = ~702 cents, give or take about 20 cents.
In 12-edo, if C is the reference pitch at 0 degrees, then following the circle counterclockwise thru the sharp keys and clockwise thru the flat keys, gives us 5 pairs of notes which have the same pitch, and are thus enharmonically equivalent:
In 19edo, the circle shows us that outside of the 7 diatonic notes in C-major, all 12 of the other notes have double names.
(In this diagram the conventions are different than in the one above: C is at the top, clockwise goes thru the sharp keys and counterclockwise thru the flat.)
For the 31-edo circle, the degree numbers of the notes are shown along with the letter notation.
For the 53-edo circle, the degree numbers are shown.
Blackwood, Easley. 1985.
The tonalsoft.com website is almost entirely the work of one person: me, Joe Monzo. Please reward me for my knowledge and effort by choosing your preferred level of financial support. Thank you.