How do you test MOSFET in laptops ?

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  • Jane
    Senior Member
    • Aug 2010
    • 188

    #1

    How do you test MOSFET in laptops ?


    I tried to use this method:

    Testing an N-channel MOSFET:

    Step 1: Discharge the Gate (turn off the MOSFET)
    Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
    Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.

    Step 2: Charge the Gate (turn on the MOSFET)
    Now, place the red probe on the Gate (G) and the black probe on the Source (S). This charges the Gate and turns the MOSFET on.

    Step 3: Check for Drain-Source Continuity
    After charging the Gate, place the black probe on the Source (S) and the red probe on the Drain (D). If the MOSFET is functional, the multimeter should now show low resistance or some continuity.

    Step 4: Discharge the Gate Again
    To turn the MOSFET off again, place the black probe on the Gate (G) and the red probe on the Source (S). Afterward, place the black probe on the Source (S) and the red probe on the Drain (D) – the multimeter should now show no continuity (high resistance).


    Is this method correct?
    I can not measure low resistance, after openning the MOSFET - see step 3. Does it mean my multimeter does not provide enough voltage to open the MOSFET?

    I tried with 4468 MOSFET
    https://alltransistors.com/adv/pdfvi...f&dire=_aosemi

    Or do you use a better way for testing that is good enough ?

    Thank you for advice.
    Click image for larger version  Name:	dataurl429224.webp Views:	0 Size:	238 Bytes ID:	3469629
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