>>Needs to be as cheap as possible.

> OK, but how cheap is cheap enough? Digikey sells 1W 2512 size SMD
> resistors in 1mOhm to 20mOhm range  at $0.77/pc - search ERJ-M1WS.
> Use next higher value and add a voltage divider in parallel (or even
> a trimpot) to get desired voltage/FS.

1.    Too dear.
And without looking I suspect those resistors lack the temperature 
invariance.

2.    It's a current sense resistor and needs to be the correct value 
by itself.
Current is up to 5A but usually less. Target sense voltage is 100 mV 
but may be higher or lower with circumstance.

But, as I noted, I want to be able to 'roll my own' so that I have 
proper control of the characteristics in prototype and low volume use. 
If it ever gets to anything like volume OTS parts may suffice.



        Russell 

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