I designed a Galvanic skin response meter , it works well as per the circuit attached , The difference amplifier works as per formula . But the voltage divider combination when connected with Input of a Differential amplifier gives values not as per the voltage divider formula , i need to calculate how this voltage generated across the circuit on what calculation basis . Kindly help me . i tried all possible combinations . Hope i miss something basic . Help me please ,. Circuit multisim simulation file screen shot attached .