Resistor with "1:R2" printed on it.....what value should I read?

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  • Francesc V.
    Tempus fugit
    • Nov 2022
    • 221
    • Catalonia

    #1

    Resistor with "1:R2" printed on it.....what value should I read?

    Has this two dots any meaning? Because there are several and I would say they measure about 11 ohms.........however, my common sense tells me that they should be 1.2 ohms........right?

    It's a 1210 SMD resistor, just if it helps.

    Regards,
    Francesc.
  • truclacicr
    Badcaps Veteran
    • Apr 2019
    • 293
    • australia

    #2
    I would think the same as you. I don't recall ever seeing that marking style, though. Can you show us the whole PCB? Maybe we could infer an appropriate value by determining the functions of the resistors in the circuit.

    Comment

    • Francesc V.
      Tempus fugit
      • Nov 2022
      • 221
      • Catalonia

      #3
      Click image for larger version

Name:	IMG_20250611_073820_907.jpg
Views:	58
Size:	1.63 MB
ID:	3657125It belongs to a Schneider Solar Inverter
      Attached Files

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      • truclacicr
        Badcaps Veteran
        • Apr 2019
        • 293
        • australia

        #4
        It seems to me that the resistor should carry a reasonably high current, so 11 ohms doesn't make sense.

        Comment

        • Francesc V.
          Tempus fugit
          • Nov 2022
          • 221
          • Catalonia

          #5
          These two dots, with a little bit of imagination turns into an 8 (eight)...............so I guess that these resistors might be 18R2 :-)
          It makes sense as long as some in the circuit measure 18.4

          What do you think?? Do we accept an eight? xDD

          Comment

          • petehall347
            Badcaps Legend
            • Jan 2015
            • 4425
            • United Kingdom

            #6
            googles take on it ..
            The image shows two surface-mount resistors, both marked with "18R2", which indicates a resistance value of 18.2 ohms. These resistors are likely metal foil resistors, known for their precision and stability, and used in applications requiring accurate resistance values.
            Foil resistors are constructed with a thin metal foil mounted on a ceramic substrate, offering excellent heat conductivity. The markings "18R2" denote a resistance of 18.2 ohms, with the "R" acting as a decimal point. These components are typically used in circuits where precise current control or voltage regulation is needed.​
            Last edited by petehall347; 06-11-2025, 03:05 PM.

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            • truclacicr
              Badcaps Veteran
              • Apr 2019
              • 293
              • australia

              #7
              Try to determine how much current those resistors are required to carry in that circuit, then calculate the wattages to see if they make sense.

              FWIW, D10 is a 1A 40V Schottky Diode (VS-10BQ040-M3/5BT):

              https://lt.rsdelivers.com/product/vishay/vs-10bq040-m3/5bt/vishay-40v-1a-schottky-diode-2-pin-do-214aa-vs-m3/5bt/5431566P

              https://www.vishay.com/docs/93335/vs-10bq040m.pdf
              Last edited by truclacicr; 06-11-2025, 06:28 PM.

              Comment

              • Francesc V.
                Tempus fugit
                • Nov 2022
                • 221
                • Catalonia

                #8
                Thank you all for the responses and your time.

                Comment

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