Identifying electronic component

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  • Askic
    Senior Member
    • Sep 2018
    • 187
    • BIH

    #1

    Identifying electronic component

    Hello experts,

    do you have any idea what are the components labeled with letter V on PCB?

    I cannot measure resistance with the multimeter (it's probably very high). There is a picture in the attachment. These elements have some kind of protective function. One side is connected to the ground.


    Thank you in advance.
    Attached Files
  • stj
    Great Sage 齊天大聖
    • Dec 2009
    • 30990
    • Albion

    #2
    Re: Identifying electronic component

    they are probably some form of zener diode

    Comment

    • R_J
      Badcaps Legend
      • Jun 2012
      • 9535
      • Canada

      #3
      Re: Identifying electronic component

      Can you post a large picture of the component? 455x134 is too small to make out the logo. is it C? 9CA I suspect they are tvs components
      Last edited by R_J; 11-12-2020, 11:03 AM.

      Comment

      • Askic
        Senior Member
        • Sep 2018
        • 187
        • BIH

        #4
        Re: Identifying electronic component

        Thanks for the feedback.
        This is the best picture I can do, because the components are tiny.
        It is written CM 9CA and the logo is very much like Toyota.
        This is the analog input card of the PLC (receives thermocouples). These are the first elements that have connection to the thermocouple in the field. When there is an overvoltage they usually go short to the ground.
        Attached Files

        Comment

        • stj
          Great Sage 齊天大聖
          • Dec 2009
          • 30990
          • Albion

          #5
          Re: Identifying electronic component

          bi-directional TVS diode - probably 9v

          Comment

          • PeteS in CA
            Badcaps Legend
            • Aug 2005
            • 3579
            • USA, Unsure of Planet

            #6
            Re: Identifying electronic component

            Originally posted by stj
            bi-directional TVS diode - probably 9v
            My thinking, too. The logo looks like that of General Semiconductor (a division of Vishay).
            Last edited by PeteS in CA; 11-13-2020, 12:58 PM.
            PeteS in CA

            Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
            ****************************
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            Comment

            • R_J
              Badcaps Legend
              • Jun 2012
              • 9535
              • Canada

              #7
              Re: Identifying electronic component

              I think they are Vishay bi-directional Transzorb SMBJ33A (CM) I suspect the 9CA could be date/mfg code
              The ones marked MM are directional type. Here is the same part with a different date code
              Attached Files
              Last edited by R_J; 11-13-2020, 06:18 PM.

              Comment

              • Askic
                Senior Member
                • Sep 2018
                • 187
                • BIH

                #8
                Re: Identifying electronic component

                Thank you very much for the information. I couldn't test it with multimeter set to test diodes and therefore I was confused. Now, from the datasheet I can see that the applied voltage must be higher in order the diode to start conducting.
                Last edited by Askic; 11-15-2020, 02:49 AM.

                Comment

                • stj
                  Great Sage 齊天大聖
                  • Dec 2009
                  • 30990
                  • Albion

                  #9
                  Re: Identifying electronic component

                  that's how it works, when the voltage rises above the level safe for the circuit, the diode turns on and shorts the voltage to ground.

                  Comment

                  • Askic
                    Senior Member
                    • Sep 2018
                    • 187
                    • BIH

                    #10
                    Re: Identifying electronic component

                    Hello guys,

                    can you please help me identify components show in the attached picture?
                    I have found that component nr. 1 is tantalum capacitor, most likely 33 uF, 16V
                    https://cdn.badcaps-static.com/pdfs/...88116449c7.pdf from manufacturer Vishay.
                    However, I'm not sure what components 2 and 3 are. They are most likely produced by Vishay and they some kind of Zener or TVS diodes, but I'm not sure if this 25A means 25 amperes. It sound a lot to me.
                    I hope you'll be able to help me.

                    Thank you very much.
                    Attached Files

                    Comment

                    • diif
                      Badcaps Legend
                      • Feb 2014
                      • 6978
                      • England

                      #11
                      Re: Identifying electronic component

                      Yes, they are TVS diodes.
                      Attached Files

                      Comment

                      • Askic
                        Senior Member
                        • Sep 2018
                        • 187
                        • BIH

                        #12
                        Re: Identifying electronic component

                        Originally posted by diif
                        Yes, they are TVS diodes.
                        Thank you!

                        Comment

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