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Voltage is dropping down

  1. Jun 19, 2013 #1
    Voltage is dropping down !!!

    Hi Folks,

    I have designed a rectifier and regulator for RFID Tag. Both are working fine when they are simulated independently.
    When I gave 500mV as input to 4-stage rectifier, I got 1V output for open load ckt condition.

    Now, I have connected rectifier to regulator. Rectifier output is 500mV. What may be the reason? Because of the load, current decreases. That is fair. But why voltage is decreasing? Any clue. When regulator has run independently, it consumes 836nW of power. I am in desperate need of help. Pls help me.
  2. jcsd
  3. Jun 19, 2013 #2


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    Open circuit voltage of an unregulated voltage source will always be higher than when a load is applied

    your description seems a bit odd .....
    what does that mean ?

    what sort of regulator ?

    would you please like to show a circuit diagram of your project so it could be understood and fault diagnosed easier :)

  4. Jun 19, 2013 #3


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    You "gave the circuit 500mV".
    Was this 500mV RMS? / Peak?
    These simulators have a lot to answer for, you know. They make it possible to launch into things you may just not be ready for. What actual answers were you expecting, on the basis of your knowledge of electronics - and why?
  5. Jul 18, 2014 #4
    I'm new here, but what if you hooked up the rectifier incorrectly? Could you wind up with a voltage multiplier with what you have? that would explain it, also don't forget that a diode will drop approx 1.5 V.

    I just caught the tail end of this, but having used simulators before, I was quite impressed with they're usefulness and they seemed to work very well.
  6. Jul 18, 2014 #5


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    Imo, where simple circuits are concerned, all simulators do is to save the trouble of building something but they can often be used as a substitute for
    1. Thought
    2. Learning stuff.
    But then, I still value the idea of knowing your multiplication tables.
  7. Jul 18, 2014 #6


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    Even commercial linear regulars, such as the LM7805, need some head room.

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