Voltage-4 to 20mA Current Transmitter

OP07 has low drift (maximum voltage drift 30 FLV, maximum temperature drift 0.6vV/aC), low noise (maximum
0.6 pLVp.P), ultra-stability (maximum 0.6yV/qC.month), and wide power supply voltage range (t3~ +18V) high performance
operational amplifier. The parameters of OP27 are relatively close to OP07 (see details).
    Their pin function diagram is shown in Figure LO-l, and the application circuit is shown in the figure.
When R3:R4, Ri=R2, OP07 forms a differential instrument amplifier, and the amplifier gain is determined by R3/RI.
The figures below are two examples of commonly used circuits of operational amplifiers. The circuit structure is the same as that of a general operational amplifier
.
    This circuit can amplify the input signal of the sensor and convert it into a 4~20mA current output. The circuit is mainly
composed of an operational amplifier, a reference voltage source, and an output tube. The input voltage is amplified by the operational amplifier and driven by V. After passing through the sampling resistor R6
, it reaches the load resistor Ri. output in the form of current. The relationship between the output current and the input voltage
is     /ou-r=(VIN×Rs/Rz +5Rs/R,)/R6
    according to the parameters in the figure
    /ourr=(16VlN/JOO) +4.O(mA)