Dear all,
I got the circuit for constant current source using op-amp known as howland current source. I have attached the circuit diagram. I got 5.2mA constant current at variable load from 10 ohm to 5k ohm. Vin is limited to 12V and expected output current should be 8mA. Please anyone suggest me what to change in this circuit so that i can get 8mA constant current.
I simulated this circuit in LTspice when i change the value of R (R1,R2,R3,R5) below 2.3k then i have getting constant current at variable load.