It is widely known in the industry that power transmitter is a device that converts measurement parameters (such as current, voltage, power, frequency, power factor, etc.) into DC current and DC voltage and isolates the output analog signal or digital signal.

Power transmitter is a measuring instrument that converts measuring parameters (AC current, AC voltage, active power, reactive power, active power, reactive power, frequency, phase, power factor, DC voltage, DC current, etc.) into DC current or voltage (electrical energy pulse output) in linear proportion. Widely used in electric power, petroleum, coal, metallurgy, railway, municipal government and other departments of electrical measurement, automatic control and scheduling system. The analog signal current value of the international standard output of the new transmitter is 4~20mA two-wire loop, which is widely used in sending data and controlling some actuators that are easy to accept the standard instruction. Current telemetry has been used as the only technology yi standard in analog signal in the world. In a current telemetry circuit using two wires, the transmitter's operating power supply and reading device, including the sensor's operating power supply and any other resistors of the sending wire, are in series in the loop.

According to the general block diagram of the power transmitter, the working principle is analyzed, and according to the technology used, all the components listed in the diagram are not indispensable. The transmitter in the figure measures a voltage and a current signal. Usually the product of the voltage and current signal is the power of the circuit under test. A power transmitter can be a power transmitter measuring a voltage, current and corresponding power, or a voltage transmitter measuring a single or multiple voltage, or a current transmitter measuring a single or multiple current.