- I to V converter :- Current to voltage converter is required for circuits which need off In the form of voltage to control the further process. The converters are required to control the solenoid valves of actuator or valves. The voltage obtained at the O/P of the convertor is proportional to change of current at the input. If instrument which requires O/P in the form of voltage has I/P imedance very large than the converting resistor then the O/P can be easily obtained by using simple resistor circuit. But if the value of converting resister is larger than the input impedance of the instrument then the convertor with op-amp. The current to voltage converter is analyze by using KCL, If the KCL is applied at inverting voltage then,
Vout−VRf=Ip+I−

As The O/P is connected to inverting V through feedback resistor Rp. Negative feedback configuration of op amp is given as V−=V+=0. Assuming I−=0 and the output voltage is obtained by follow equation -
Vout=IpRp
- V to I convertors :- In this circuit the load resistor RL is kept floating and not linked to ground. In input voltage Vin is given to non-inverting terminal. The feedback voltage across the the load resistor RL is used to drive the inverting terminal. The load voltage is in series with VD voltage i.e. the differential voltage between both the I/P terminal. The load voltage is in series with VD voltage, the differential voltage between both the I/P terminals. The load current is used to determine the feedback to voltage.

For the input loop, the voltage equation is -
Vin=VD+VF
Since F is very large,
VD=0
So, Vin=VF
Since, the input to the op−amp.
IB=0
Vin=IL∗R
Therefore, II=IL=VinR
To determine the load current e should known the I/P voltage and I/P resistance between IL<Vin.
The load current is directly proportional to input voltage and controlled by resistor R.