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Jemshah
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Asked: 2023-01-01T09:24:17+00:00 In:

Outline the procedure of testing P-N junction diode for defects.(4 marks)craft1 electrical June/July 2020

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Outline the procedure of testing P-N junction diode for defects.(4 marks)craft1 electrical June/July 2020

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    Enlightened
    1. Set up the test equipment: Connect a digital multimeter (DMM) in the “diode test” or “continuity” mode to the diode under test, and ensure that the DMM is properly calibrated.
    2. Test the forward bias characteristics: Apply a small forward bias voltage to the diode (usually around 0.7 V for a silicon diode). The DMM should show a low resistance (indicating a low voltage drop) when the diode is forward biased. If the DMM shows a high resistance or an open circuit, this could indicate a defect in the diode.
    3. Test the reverse bias characteristics: Reverse the polarity of the applied voltage, so that the diode is now reverse biased. The DMM should show a high resistance (indicating a high voltage drop) when the diode is reverse biased. If the DMM shows a low resistance or a short circuit, this could indicate a defect in the diode.
    4. Test the breakdown voltage: Slowly increase the reverse bias voltage applied to the diode. At a certain point, the diode should break down and the DMM should show a low resistance. This indicates the breakdown voltage of the diode. If the diode does not break down or the DMM does not show a low resistance at any applied voltage, this could indicate a defect in the diode.
    5. Test the recovery time: After the diode has broken down, remove the reverse bias voltage and measure the time it takes for the diode to recover. If the diode does not recover or takes an excessively long time to recover, this could indicate a defect in the diode.
    6. Test the temperature coefficient: Measure the forward voltage drop of the diode at several different temperatures and compare the results. If the voltage drop varies significantly with temperature, this could indicate a defect in the diode.
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