If you do make a change to that 4.7K resistor - *please* go to a value that's only available in 1% resistors. Using a part that one can get in 20% is just asking for trouble. Yes it's the standard and it's way to late to change a standard. These days, the cost of 1% parts is a fraction of a cent. Having a 1% thermistor that costs $3 and a 20% resistor that saved you $0.002 just isn't right. Yes most parts are 1 or 2% no matter what you spec. Every once and a while you loose that bet.
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If you do use an isolated supply (which is what I do), put a bleed resistor to ground. There's always the strange case of leakage from this or that. You *could* get the ground up to something really silly. Yes I need to do that on the power supply sitting by my feet .... I should read my own posts ...
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If you do use an isolated supply (which is what I do), put a bleed resistor to ground. There's always the strange case of leakage from this or that. You *could* get the ground up to something really silly. Yes I need to do that on the power supply sitting by my feet .... I should read my own posts ...