DC CHOPPER CIRCUIT  (chp_para.cir)
.PARAM RON = .001              ;establishes RON as a parameter
.STEP PARAM RON LIST .001 .1 1 ;three runs using .001, .1, and 1 for RON
VS 1 0 DC 24                                      
Rload 1 2 5                                       
S1 2 0 10 0 SMOD                                  
.MODEL SMOD VSWITCH(RON={RON}) ;use the parameter in { }
VCONTROL 10 0 PULSE(-2V 2V 0 1US 1US 10MS 25MS)  
.TRAN .1MS 75MS                         
.PROBE                             
.END