Good points, Jay.
On the double supply version, the scaling factor is wrong. You have 8 x 0.2 resistors in parallel so the scaling is 25mV / A:
Actually, there are 5 pairs of resistors, at 0.2. I included five MOSFETS. I just replicated the MOSFET nodes, from the simulation circuit. I don't know how to do the math, to get 50
, but, if you want me to use it as a learning exercise and correct it, I would be glad to do that. We probably need to add a note, to the schematic, about adjusting the resistor values, based on the number of MOSFETs.
Here are some comments on the input connector: The schematic shows the part as conn_0.1x2, which suggest this type of connector: The current rating of the connector is determined by the size of the wire you can attach to the mating part. This is limited to 22 awg (0.32 mm2) which is about 1A. I would use something else.
One of the great advantages of KiCad, is that the schematic symbol does not dictate the board component. This is a good example. The schematic specifies what I thought to be a generic connector, of any type, having two pins. For the unit I will be building, I will be using banana jacks. I will assign the banana jack footprint to the generic two-pin connector symbol, with the component assignment function. But, not everyone may want banana jacks.
Because you have made me aware that this particular two-pin connector symbol actually specifies the connector you showed, I will see if there is not a banana-style connector symbol. Or, would you think some other type connector would be better?