macro preamp R3=5.6e3 R4=2.0e3 R5=1.0e3 beta=90. Vcc=5.0 I0=2e-15
  call preamp.f77([R3],[R4],[R5],[beta],[Vcc],[I0])
  message 'Initialized preamp model with the following values'
  message '  R3 = ' [R3] ohms
  message '  R4 = ' [R4] ohms
  message '  R5 = ' [R5] ohms
  message '  beta = ' [beta]
  message '  Vcc = ' [Vcc] Volts
  message '  I0 = ' [I0] Amperes
return