Titulo: Circuito Inversor c/ transistor bipolar NPN 

* fontes de tensao
vcc 1 0 dc 5
*vin1 3 0 pulse(0 5 0 0 0 100n 200n)
vin1 3 0 pwl(0n 0v 50m 0v 100m 5v 200m 0v 250m 0v)

* descricao do circuito
r1 1 2 470
r2 3 4 2.2k
q1 2 4 0 transistor

* comandos de execucao
.model transistor npn (bf=75 rb=100 cje=1pF cjc=3pF)
.tran 0.01m 250m
.print tran v(2) v(3) v(4) 
.end