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AMC1200: Measure line-to-line voltage

Part Number: AMC1200

Hi Team,

Our customer would like to confirm if he can use the AMC1200BDUB for the application below. According to the customer,

We would like to measure line-to-line voltage (see pptx).  From looking at the voltage measurement example, it seems that L2 is grounded?  Our high-voltage system does not have ground or neutral.  The electronics are powered by an isolated AC/DC power supply.  Can I measure line-to-line voltage, as indicated by the pptx picture?

voltage measurement on AC lines.pptx

Thank you for your support!



  • Hi Danilo,

    No, a system ground or neutral is required to terminate the high voltage divider circuits. As connected right now, the Mohm resistors create a line-line fault with high voltage from both phases at the inputs of the AMC1200. Additional resistors to system ground or neutral need to be added. Please see attached TINA schematic for an example implementation. 


    Make sure the customer reviews the absolute maximum ratings table, especially the high side power requirements and input common-mode voltage level requirements. 

    L2 is typically connected to device ground and the shunt resistor as it holds the input voltage within the common-mode input range with respect to the device ground for in-line current measurements. When measuring line to line, this connection to ground is not possible and the input common-mode voltage must be ensured another way.