Calculating Zener current in a Zener regulated power supply?

Discussion in 'General Electronics Chat' started by Pinky Ringz, Dec 2, 2009.

  1. Pinky Ringz

    Thread Starter New Member

    Oct 4, 2009
    6
    0
    Zener regulated power supply circuit lab

    DFO6M integrated cct bridge rectifier
    1N4742 zener diode (12v)
    25 vrms c.t. transformer
    1 - 220uF/50V min. capacitor
    2 - 1.2k resistors in parallel in the circuit
    1 - 1k ohm resistor for load

    i do not remember how to calculate the zener current. Can anyone help?
    Also, how can i draw ccts on the computer with all the icons and values in it so i can use these boards better?

    Thank you for your time either way!!

    Thomas
    1st year electrical engineering student
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    The important specs here are the zener wattage, which is very analogous to resistor wattage, it sets up the maximum current through the zener diode. Real world design you have to figure out if the load will ever be removed, since the zener will have to absorb the excess current.

    Zener current is Ohm's Law, with the zener being a fixed voltage in the equation. You use the remaining voltage across the resistor to calculate the current through the fixed resistor.

    http://www.allaboutcircuits.com/vol_3/chpt_3/11.html
     
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