Updating my Milliohmeter

[namster]

for my final years project , i realised a prototype of milliohmeter , the resulte haven't been very concluante , I want to quote the differnetes problèmes to fix .

• for thermal emf compensation i use a H bridge to inverse the current but when measuring using  a Tti 1604 it wasn't symetrical i think that the idss of Mosfet cause leakage current
• after amplification using a INA118 i use a absolute value circuit formed of U11 U10 (OP07 and INA105 ) , wasn't linear 
• for acquisition i realised a multislope ADC but the resolution was lower than 12bits , i have to replace this one in future version of the instrument 

there is some pictures inside the instruments ,https://imgur.com/a/UYK7Ut1