In the experiments we have done till now we have designed gates by arranging transistors in various fashions .The simulation of these designs gave graphs of output voltages and we analyzed how these graph changes with varying different parameters of the transistor. Now when you place a transistor on screen there is a back end code which tells a simulator what are the points to which the transistor's substrate,gate,drain,source are connected. The language in which this information is conveyed is spice.
INTRODUCTION TO SPICE
Spice stands for Simulation Program for integrated circuit emphasis.The PC version of spice is called PSPICE whereas HSPICE works on larger workstations.Spice can be used for designing and analysis of various kinds of circuit analysis and van include various components: resistors,inductors,switches,MOS transistors,digital gates etc.