Resistors' bridge resistance formula

 extends :: https://frmth.blogspot.com/2020/07/resistor-bridge.html 

such became a question or potentially required in the midst of some other research

( ↑↓ the related Fig. ↑↓ )

Extended/complex dif. op amp biasing formula re-derivation

 interestingly - the 1-st time i attempted this (a year or more ago) it went to heywire = i was not able to tie in the input chain part ~ although now it seemed trivial

such scheme (R_a,R_b(,R_g)) would be trivial for a non R2R input comparator as LM393 especially at low supply voltage levels