Help with LTSpice Simulations

Discussion in 'Homework Help' started by ztjust, Apr 1, 2012.

  1. ztjust

    Thread Starter New Member

    Apr 1, 2012
    Hello, I'm having some issues getting a couple of my LTSPice Simulations to work.

    The first is a voltage multiplier/rectifier. I want to be able to find the DC output voltage across the resistor.

    The second is a Logarithmic converter and I need to increase the voltage from 0.25 to 5 volts in increments of 0.25 volts.

    I attached the two SPICE schematics. View attachment Lab7A.asc

    View attachment Lab7B.asc

    I'm just having issues running the proper simulations on these to get a DC output for them.

    Thank you for any help.
  2. crutschow


    Mar 14, 2008
    The problem is you are only doing the DC operating point (.OP) for both simulations which only gives you the initial static DC operating point.

    To remedy this, for Lab7A do a transient simulation command (.tran 200ms).

    And for Lab7B, do a DC sweep command for V3 (.dc V3 0.25 5 0.25).

    In each case, after running the simulation by clicking on the "running man" icon, just click on the node in the schematic for which you want to view the voltage.