Current Source 4-20 mA PUBLIC

Simple 4-20 mA Current Source, suitable for instrument or process controller/recorder calibration

Precision Resistor R2 will enable 1-5V calibration. Load Line Characteristics should define the maximum RL value. Op Amp should be low noise, temperature compensated, industrial grade LM301 or better JFET input. Can also be used with a Precision Voltage Reference like AD584 and a thumbpot voltage divider, providing precision and repeatability required for instrumentation calibration. Offsetting and or balancing may be evaluated on a real circuit (bias resistors, balancing, etc)