Non real world Constant current sources Comparison

NB! :: the brought circuits are not tested in reality -- they only represent a technical hint to a "What such grids may behave like" -- they are modifications from std. current source cirquits

the long story short -- THE TEST ::

here's no intentional temperature compensation = in real there is likely a significant difference to these plots

note:: the last shown (the lowermost fig. , right) is actually been built but tested near-around-below of it's 5V range (not entirely) -- however it worked better after replacing the HiFq-LoPwr transistors of the shown "zener" with MedLoFq-LoPwr 1-s (that is lowering the "starting point" of a zener - with expense of it's precision x (overall) range loss) -- which however improved the current source in low voltage range

by that i reworked my "zener" concept - finding the following being (/!\) most likely the best (/!\) to use
however this one has a "startup ramp" ...

... i won't show here the "zeners" without "startup ramp" -- coz the're not tested in real
NB! this "zener" HAS a "startup ramp" (remove the capacitors -- and it nastily shows out)