i can't fully understand how diode works in parallel

Discussion in 'Homework Help' started by regal009, Jul 9, 2011.

  1. regal009

    Thread Starter New Member

    Jul 9, 2011
    i don't know how diode works in parallel
  2. MrCarlos

    Senior Member

    Jan 2, 2010
    Hello regal009

    Theoretically, the voltage drop in a silicon diode is approximately 0.7V.
    In this particular case (for the attached image) only current flowing through the diode located on the right (D1)--Sorry Say LEFT--

    We are applying to the circuit: +15 V and +10 V. therefore the circuit image, just feel +5 V.

    Remember: V / I = R, or V / R = I, or RXI = V
    Then: 5 - 0.7 = 4.3V which is approx. What it is showing the XMM1 voltmeter.

    The voltage drop across D1 is displayed on the voltmeter XMM2 which is very approximate 700mV.

    The current flowing through the circuit D1, R1 is indicating on the XMM3 meter which is 1.97mAmp.
    4.3/2200 = 0.001954Amp. = 1.1954mAmp.

    Through the diode D2 is no current because it is reverse biased.

    But ... if we apply alternating current to that circuit then the results will be different from what we've been seeing.

    at your service
    Last edited: Jul 11, 2011
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Hi. I'm not sure if I'm seeing a different image than the previous poster, but for me the diode on the left is forward biased, means conducting. Also I only see "V out", not saying what it is referenced to. If it's the voltage drop over the resistor, I agree that it is about 4,3V.

  4. lazukan

    New Member

    Mar 29, 2011
    The current will flow through the path where the voltage difference exists , so it will activate one of the diodes and the opening voltage of the diode is aproximately 0.7 volt , so the voltage across the resistor is 5-0.7= 4.3 v

    About the other diode , there will be reverse biase current across it but you can ignore it since it is at the values of picoamps