The measured parameters of the power transmitter include AC current, AC voltage, active power, reactive power, active energy, reactive energy, frequency, phase, power factor, DC voltage, DC current, etc. Electric quantity transmitters are widely used in electrical measurement, automatic control, and dispatch systems in departments such as power, petroleum, coal, metallurgy, railways, and municipal governments. The analog signal current value output by the new transmitter international standard is 4-20mA, and the two-wire loop is widely used in the process of transmitting data and controlling certain actuators that are easy to accept instructions according to this standard. It has become an international standard for current telemetry technology in analog signals. In a current telemetry circuit using two wires, the working power supply of the transmitter and the reading device, including the working power supply of the sensor and any other resistors of the transmitting wire, are connected in series within the loop.