Remember: dependent sources are your friends when synthesizing nonstandard SPICE components.
Most SPICE variants give you a way to make a bilinear dependent source. In ngspice, for example, you can use a "B" device to make a resistor whose voltage is proportional to the product of the applied current (measured by a series "ammeter") and a control voltage. A pair of these with complemetary control voltages should make a voltage-controlled pot (although I haven't tried this particular trick). This is enormously more flexible than a swept resistor. You can sweep the control voltage if you wish, but you can also do a transient analysis using an arbitrary function for the control voltage. John Doty "You can't confuse me, that's my job." Home: [EMAIL PROTECTED] Work: [EMAIL PROTECTED] On Mon, 5 Jan 2004, John Sheahan wrote: > On Sun, Jan 04, 2004 at 09:15:55PM +0100, [EMAIL PROTECTED] wrote: > > Hi Stuart, > > > > I did some simulations today using ".dc name start end stepsize" so that > > would mean for your example > > > > Resistor sweep test circuit > > r1 0 1 100 > > r2 1 2 1k > > v1 0 2 1v > > .dc r1 100 1k 100 > > .end > > > > This way it works and generates values, but shouldn't the result be a > > straight line? > > > > > > Tobias > > this circuit has the transfer function vout = v1 . r1 / (r1+r2) > which is not a linear function of r1 (not a straight line) >
