Hi, much later... I was drawing the tracks and "pads" on a copper-clad board most of the afternoon, and before that checking if that circuit works with everything including the CCS resistor on +5V, but it doesn't because the ADC shows no reading, I imagine the input voltage is too low like that so I'll leave it as it is (functioning).
"447mΩ x 100mA = 44.7mV, not 4.49V." ...very correct, I originally tried to use a 100V/V current shunt monitor to boost the input voltage, but as it adds input noise I took it off before encountering the issue that was my question, I forgot - my apologies again, I am forgetful at present with moving house soon and my big goldfish had an operation two days ago (seriously). The circuit pdf is the right wrong one though, at least that's right.
"with this design you will not get very precise results. What precision do you expect?" - Hard to define, just precise enough to not be a waste of my time and of components. It seems reasonably accurate so far: The CC is 99 - 100mA, and after a long time on (about 50 seconds to a minute) rises to 101mA, but seems to stay at 100mA.
Today, for example, The 5% 1Ω 5W reads as 0.950; the 5% 0.5Ω 3.75W reads as 0.478; and the 0R02 metal shunt resistor is a very constant 0.020Ω, even if on for over a minute. I have seen that the resistors which are under 5W creep up in value "quickly", I imagine that's the heat. Yesterday the 0.005Ω metal shunt read as 0.007Ω - 0.008Ω, and a 0.07Ω as something like 0.064Ω, a 0.08Ω as 0.072Ω, and a 5% 2.2Ω 7W as 1.996Ω. - With my ability that is more than enough accuracy...
This will only be on for 10 - 20 seconds at most, enough to get a reading. The BJT will use the cheapo FR1 38uM copper board as a heat-sink.
The LED: sorry, I checked the datasheet and saw no reference to tempco, it's a low power 3mm green through-hole LED.
On the breadboard the 9V is a very stable power supply (like a phone charger plug type), but it will be a battery for the finished circuit - things haven't worked out too well there: I'll use two 9V batteries in parallel so it lasts more than ten resistors... The 5V is a 7805 on the breadboard, but will be a TPS73801 on the circuit, and the last one I used supplied a very stable 5.02V from a battery (the other 73801 I mistakenly tried to use for the CC on the first prototype had an output of not 5.02V and 100mA but 1V and 2A!!!!! Oops.)
I'm sorry, I don't understand the part about: "...It means 35 Ohms."
...And just to finish the day well with another mistake - just take a look at the crocodile clip covers I ordered to go with the fantastic copper clips, they looked smaller in the photo:
Regards