Frequency response using SPICE in Spice Simulation - PCB design Posted May 16, 2007 · Report reply I've made a spice netlist of a circuit I am designing. The input to the circuit is an AC signal --> v1 1 0 dc 0 sin(0 34 60). Well I can do a transient analysis on this easily. But I also want to see what happens at the output as I vary the frequency. Unfortunately using .AC simply doesnt work. I suspect that I defined my signal source incorrectly to be used with .AC.Please help.Thanks.