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    N7j3a marking transistor

    Hello
    My friends
    A transistor with the following specifications:
    MARKING : N7J3A
    I am the DATASEET or its store link
    Click image for larger version. 

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ID:	154615

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    Re: N7j3a marking transistor

    Hi,

    Maybe TCM809 from Microchip?

    You need to provide more information about the whole circuit. Where is the PCB from, what does it do, what other parts are used?
    Also: connections, voltages...

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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    Re: N7j3a marking transistor

    The "N" looks different, so maybe the marking begins with "7J".
    Only "7J" is a FMMT38C, a 60V NPN darlington transistor, but I find nothing where also "3A" is included in the marking.



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  4. #4
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    Re: N7j3a marking transistor

    Quote Originally Posted by KlausST View Post
    Hi,

    Maybe TCM809 from Microchip?

    You need to provide more information about the whole circuit. Where is the PCB from, what does it do, what other parts are used?
    Also: connections, voltages...

    Klaus
    The schematic of the fragment is as follows:
    Its base is a direct 24V
    The other base is a 24 volt switch that passes through a RC filter
    Its output is connected to the relay
    The base that is filtered can also be switched on by a conventional transistor
    My guess is that this piece is a switch model
    But what model is unclear!
    I also replaced this piece with MOSFET-P but the board didn't work and also the power transistor
    Click image for larger version. 

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    - - - Updated - - -

    Quote Originally Posted by KlausST View Post
    Hi,

    Maybe TCM809 from Microchip?

    You need to provide more information about the whole circuit. Where is the PCB from, what does it do, what other parts are used?
    Also: connections, voltages...

    Klaus
    New circuit image
    I'm sure of the wiring

    I also tested the MOSFET type NDS356AP and tested with 2N2222 but both relay outputs are permanently ON
    This circuit works with the sound that whenever it receives a data, this piece of tripod operates and the voltage of the relay is supplied and then cut off and in normal mode which is always disconnected.
    But the two pieces I tested have been permanently working

    Click image for larger version. 

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  5. #5
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    Re: N7j3a marking transistor

    It isn't a MOSFET because the gate-source voltage would be 24V.
    It seems to be a bipolar PNP transistor, maybe a Darlington (depends on how much current the relay needs).
    2N2222 is NPN, so it will not work.
    Measure the base-emitter forward diode voltage (negative probe to the base) on the transistor from a working unit. If the voltage is more than 1V, it is a Darlington.
    The easiest way to measure without desoldering is to measure using the multimeter DC voltage setting on a working unit when the relay is activated.
    If you measure using the multimeter diode function when a working board is not powered, other components can disturb the reading.
    If not a Darlington, you can try a BC807.



  6. #6
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    Re: N7j3a marking transistor

    Quote Originally Posted by std_match View Post
    It isn't a MOSFET because the gate-source voltage would be 24V.
    It seems to be a bipolar PNP transistor, maybe a Darlington (depends on how much current the relay needs).
    2N2222 is NPN, so it will not work.
    Measure the base-emitter forward diode voltage (negative probe to the base) on the transistor from a working unit. If the voltage is more than 1V, it is a Darlington.
    The easiest way to measure without desoldering is to measure using the multimeter DC voltage setting on a working unit when the relay is activated.
    If you measure using the multimeter diode function when a working board is not powered, other components can disturb the reading.
    If not a Darlington, you can try a BC807.
    I think this is a switch or transistor
    Because the circuit works as follows:
    Normally the relays have no voltage.
    When the board receives a data, it outputs a pulse from the microcontroller that is connected to one of the base of the segment as shown in the image.
    This activates the microcontroller and supplies the relay voltage.
    I used bc847 board was working properly but the relay output was permanently active which should not be permanently active only when the data is being transmitted.
    The following picture is the exact voltage:
    Click image for larger version. 

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  7. #7
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    Re: N7j3a marking transistor

    It is a normal bipolar PNP transistor. BC847 will not work since it is NPN. Try BC857 or BC807.



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