THSpice netlist problems

Discussion in 'Homework Help' started by ws-6driver, Jul 25, 2012.

  1. ws-6driver

    Thread Starter New Member

    Jul 25, 2012
    The problem statement i am trying to solve is a system of differential equations:
    dx/dt = x - xy
    dy/dt = -y + xy - yz
    dz/dt = -z + .8yz

    where x(0) = .5, y(0) = .5, and z(0) = 2

    I have constructed a circuit involving integrator ckts to solve this problem. the circuit will run w/o .ic statements but the output isn't what is expected. i'm trying to resolve this issue by setting all nodes not connected to sources or involved in initial conditions to 0V using .ic statement. the problem is that, when i include these .ic statements i get a message "Singular matrix: check nodes 3:31 and 2:6 Iteration No. 2.

    the mod file i'm using for the op-amp and the .cir files are in the zip file. thanks.