Pspice simulation help asap?

Discussion in 'The Projects Forum' started by quantum94, Oct 11, 2013.

  1. quantum94

    Thread Starter New Member

    Oct 11, 2013
    5
    0
    hello....
    i am quite new to orcad and pspice.......
    i just assembled a basic circuit of a clipper.....but when i simulate it ,it gives me an error,,"There are no data values in section muber 1.Ignoring this section"..and
    then another window pops up saying that analysis failed.
    Help me out with this and help me with any errors that i may have committed.
    I have posted a couple of links about the circuit and simulation profile....please help me out..I have my xams cmg soon..!

    http://postimg.org/image/gmpc2t4mj/
    http://postimg.org/image/n4wkzg8hv/
     
  2. LvW

    Active Member

    Jun 13, 2013
    674
    100
    Summary of your simulation:
    Frequency 1 kHz (period 1msec)
    Simulatin time: 1msec.
    Saving data after 100sec
    Step size: 10sec.

    What do you expect from these inputs?
     
  3. quantum94

    Thread Starter New Member

    Oct 11, 2013
    5
    0
    ohhh.....yea...!
    oke....now i corrected the simulation profile...but i dont understand the o/p that i am getting...i mean look at the link...why is the whole region red??
    and since its a negative series clipper....it should clip off the negative region na...
    I dont understand the op that i am getting ....what changes do i need to make??
    Links:
    http://postimg.org/image/l2q886e5v/
    http://postimg.org/image/jksgiqs01/
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,001
    3,229
    You are simulating a 1kHz signal for 60 seconds which gives you a solid wall of signal. (Why are you simulating for such a long time?) If you want to see the individual waves reduce the simulation time to 5ms (which will give 5 cycles of a 1KHz signal).

    If you want to see the clipping you will need to more than a 50mV signal since it takes about 0.6V to get any significant current through a silicon diode.
     
    quantum94 likes this.
  5. w2aew

    Member

    Jan 3, 2012
    219
    64
    In addition - your input is only 50mv, not enough to even turn the diode on. Try simulating over a much shorter time period (like 10ms), and with a larger input signal magnitude.
     
    quantum94 likes this.
  6. quantum94

    Thread Starter New Member

    Oct 11, 2013
    5
    0
    okee....ty....i got the op ...but it looks a bit distorted..I want a proper sine wave...what to i do to fix it?
    M simulating for 5ms with VAMPL=1V.
    http://postimg.org/image/9h2ycmku5/

    also...i have a doubt? what does the term AC refer to besides the voltage source in ORCad[look at the link in my previous posts]....i have set it to 10[just a random no]?
    And if I wish to simulate the diode characteristics..what changes I have to make in simulation profile...and which markers I have to place...and where?
     
    Last edited: Oct 12, 2013
  7. crutschow

    Expert

    Mar 14, 2008
    13,001
    3,229
    A 1V sinewave barely turns on the diode in the forward direction since the diode drops about 0.65V. Try several volts. If you want a low level rectifier than a Precision Rectifier using an op amp would be better.

    AC refers to the source voltage for the small signal AC simulation mode which uses linear models for all parts. For simulating a non-linear circuit, such as with a rectifier, you need to use the transient response that uses non-linear models and has an AC large-signal simulation mode. Both modes can use the same source but the voltages for each mode are separately stated.
     
  8. quantum94

    Thread Starter New Member

    Oct 11, 2013
    5
    0
    okee....ty....i got the op ...but it looks a bit distorted..I want a proper sine wave...what to i do to fix it?
    Also y is it decreasing the amplitude of op voltage...shouldnt it remain same?since it only clips off the negative region....?
    M simulating for 5ms with VAMPL=1V.
    http://postimg.org/image/9h2ycmku5/

    also... what does the term AC refer to besides the voltage source in ORCad[look at the link in my previous posts]....i have set it to 10[just a random no]?
    And if I wish to simulate the diode characteristics..what changes I have to make in simulation profile...and which markers I have to place...and where?
     
  9. LvW

    Active Member

    Jun 13, 2013
    674
    100
    * Use a better resolution (time step smaller - at least by a factor of 10)
    * The program ignores the AC specification during transient simulation; it is used for ac run only - which, however makes no sense for non-linear circuits.
     
  10. crutschow

    Expert

    Mar 14, 2008
    13,001
    3,229
    Did you not read my post #7?

    The diode drops about 0.65V in the forward direction so the output will be reduced by that amount.

    To measure the diode characteristics you add an ammeter to measure the current through the diode and plot that against the voltage across the diode.
     
    quantum94 likes this.
  11. quantum94

    Thread Starter New Member

    Oct 11, 2013
    5
    0
    One last thing....to edit the diode specifications....i need to do the foll steps:
    Edit<Pspice Model<Pspice Model Editor.....
    But under edit....Pspice Model option is not highlighted [link:http://postimg.org/image/rzli3jusf/].
    So how to it get it...?
     
  12. crutschow

    Expert

    Mar 14, 2008
    13,001
    3,229
    Not that familiar with PSpice to help you there. Perhaps someone else can help.
     
Loading...