Single-phase digital current/voltage measuring instrument

The utility model discloses a single-phase digital current/voltage measuring instrument, which comprises a power supply connected with each circuit. The measuring instrument is characterized in that the measuring instrument comprises an input circuit, a keying signal acquisition circuit and a communication interface circuit, wherein the input circuit is used for acquiring input current/voltage values for a microprocessor, the keying signal acquisition circuit is used for setting communication baud rate and communication address via a dial switch, the communication interface circuit adopts an RS-485 communication mode based on a Modbus protocol, receives instruct data from a host computer, uploads acquired input current/voltage data to the host computer and keeps real-time communication with the host computer. Due to the above structure and method, the measuring instrument actuates real-time measurement and display for current and voltage in electrical circuits and transmits measured electric data via RS485 interfaces. Users can optionally combine functional modules of the instrument according to needs, thereby resolving the problem that users get information only after checking the instrument, increasing precision of measurement values, keeping stable and reliable product performance and achieving easier production.