1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Mean voltage and current, rectifiers

  1. Apr 8, 2015 #1
    1. The problem statement, all variables and given/known data
    Devise the mean voltage and current in controlled and uncontrolled single device rectifier circuits with R-L series loads.
    Single circuit series circuit given of an AC voltage source, a uncontrolled diode, resistor, inductor.
    V = 240 v, F = 50 Hz, R = 10 ohms, L = 50 mH

    2. Relevant equations
    Not given

    3. The attempt at a solution
    I know that Vs = Vmaxsin(wt) , I know that in a series circuit current is the same throughout, but this is AC, do the same rules apply?
    I also know that Vav for half wave rectifier = Vpeak/pi. I found this from the fact that Vav for a full wave = 2Vpeak/pi. But is this the same for an R-L load?
    I don't know where to start in terms of the mean current.
  2. jcsd
  3. Apr 8, 2015 #2
    I assume this is the theme of what you're doing and this:
    is the specific assignment? I can guess the configuration, but you should include a schematic that shows the voltages and currents you're interested in.

    The instantaneous current is the same for series-connected elements.

    If Vav is the average voltage applied to the load, then that's only true if the load is purely resistive.

    You can start from scratch and set up the governing differential equation for the instantaneous current when the diode is conducting, solve it analytically, and find its mean over the conduction period.

    You can use the fact that the average voltage across the inductor, in steady state, must be zero to give you the average load voltage.

    Usually, though, you just do this once and substitute in specific component values. Wasn't that part of your course?
  4. Apr 9, 2015 #3
    It is part of my course but extremely poorly taught, along with a useless reading list. And that is why I have no idea how to do it. I was wondering if you know of any links or books helping to explain rectifiers? I've read through electrical machines, drives and power systems by Theodore Wildi and John Bird's electrical circuit theory and technology but neither has helped with my knowledge in regards to rectifier circuits.

    And it's not really an assignment or homework for that matter, but I was told to post it in this part of the forums. The question is more for my personal revision rather than homework.
  5. Apr 9, 2015 #4
    With regards to your problem statement, have you tried doing a search on Google for something like 'half-wave rectifier RL load'? I see plenty of useful information.

    Take, for instance, this book excerpt.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted