Sorry to bring this up, I thought it might be a common interest on how to choose a current sensing resistor of 1A or above.
Firstly, I have made an ultra-stable 1A current source prior to Dave's video, using similar Vishay precision shunt(Vishay VHP4 0.1 Ohm). I achieve this sub-ppm short term stability also by lowering the shunt resistance, low noise opamp and especially heat management combined.
Secondly, lower the sensing voltage from 1.25V to 0.2V/0.25V will increase the stability significantly. the voltage reference needed can be divided from a 1.25V or 2.5V Vref. Thus, an 0.2 Ohm or 0.25 Ohm resistor is required for 1A current source. For 2A or 10A current sensing, the voltage can be further reduced to 0.1V.
Thirdly, make a large heatsink for the sensing resistor. I often use the aluminium case for the heatsink.
Fourthly, move the power MOS(probably the most heat generator) outside the case like I did. Also the power supply could be a separate unit. Mine is battery powered.
And lastly, some none-Vishay sense resistors
1. Alpha Electronics, they make very good shunt resistors widely used among Japaneses instruments.
2. Isabell**, famous for precision shunt, their PBV is nice for current sampling.
3. Dale resistors, 2 wire, if the requirement is not very tight
4. Use parallel. ex 20 foil resistors of 5 Ohm, similar to Fluke A40B, where they use 960 foil resistors to measure 100A current.
