Adjustable output voltage regulator circuit diagram

The resistance value of the R2+RP+R1 branch in the circuit determines the size of the current I. This current should be greater than the input current of the operational amplifier, about I=1mA. It is also determined by the lowest value of the output voltage UAmin. Therefore, when adjusted to At the highest output voltage value, the current I should also become correspondingly larger. The value of resistor R1 should be such that the voltage on R1 is greater than 0.5V under low output voltage to stabilize the operating range of the operational amplifier. The minimum output voltage is determined by UR1+UR, and the UR integrated voltage regulator is a constant voltage. The maximum output voltage is determined by UeX(-Us+UR2). If Us=1.5V, UR2=1V, then Umax≈Ue=-2.5V.