BUCK CONVERTER
* ECE412_7.CIR
.PARAM T={1/5000} D={15/36}
Vb  4 2 PULSE(0A 5V 0s 1ns 1ns {D*T} {T}) ;Transistor base drive
Vd  1 0 DC 36V
X1  1 4 2 XNPN
D   0 2 DMOD
L   2 3 250uH IC=0A
C   3 0 100uF IC=20V
R   3 0 10ohm
.SUBCKT    XNPN       1       3       2   ; Home made NPN
*          name   collector  base  emitter
S1    1  6  5  2 SMOD
D1    6  2 DMOD
Rb    3  4 1ohm
Vb    4  2 DC 0V
RT    2  5 2ohm
CT    5  2 0.1uF
F1    2  5 POLY(1) Vb 0 50
.MODEL SMOD VSWITCH(Ron=0.001 Roff=10K Von=0.1V Voff=0 )
.MODEL DMOD D(N=0.001)
.ENDS XNPN
.MODEL DMOD D(N=0.001)
.TRAN 5us 1ms  UIC
.PROBE
.END