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From where we measure current in a pn junction diode

  1. Nov 7, 2015 #1
    Please any one explain me from where we measure current or we apply ammeter in a pn junction diode to measure current
     
  2. jcsd
  3. Nov 8, 2015 #2

    collinsmark

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    I suppose if you truly wanted to measure the current, then yes, placing an ammeter in series with the diode would be your only option.

    But you can also measure it indirectly by measuring the voltage across a series resistor (i.e., a resistor that happens to be in series with the PN junction), and then dividing that voltage by the resistor's known resistance. Usually* the circuit is designed with a series resistor anyway, so this typically isn't an issue.

    *(I say usually, but I have sometimes seen simple LED circuits where the LED (or system of LEDs) hangs directly off the battery. But you have to be careful with that; it could blow the LED. It's much safer to use a current limiting, series resistor. Or if you want to increase efficiency, use an active LED driver circuit.)
     
  4. Nov 8, 2015 #3

    Simon Bridge

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    Pretty much the same way as you'd measure current through anything really.
     
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