Hi Amin1372, * Please refer to my answer to your previous question here: https://easyeda.com/forum/topic/Simulation_4_20_mA_current_source-f7Dn71jOy * Are you asking how to; 1) simulate a 4-20mA current source in EasyEDA? or are you asking; 2) design a circuit for a 4-20mA current source which you then want to simulate in EasyEDA? The answers to these two questions are not the same so please clarify your requirements. Thanks.