[init] ' 74LS04 Astable Multivibrator
  mainwin 75 25:f=0:r=0:c=0:t=0:cls:print:print
  print"        74LS04 Astable Multivibrator"
  print
  print"              R1           R2"
  print"        +---/\/\/\---+---/\/\/\---+"
  print"        |            |            |"
  print"        |            |            |"
  print"        +-----|>o----+-----|>o----+----|>o----O"
  print"        |                         |"
  print"        |                         |"
  print"        +-----------||------------+"
  print"                    C1"
  print"                  ___      ___       ~4 volts"
  print"        Output = _   ______   ______ ~1 volts"
  print
  input"        Freq    ? ";f
  input"        R1 & R2 ? ";r
  input"        C1      ? ";c
  if f=0 and ((r=0 and c<>0) or (c=0 and r<>0)) then input"        Period  ? ";t
  print
  if t<>0 then print tab(9);"Freq    = ";1/t
  if f=0 and r<>0 and c<>0 then print tab(9);"Freq    = ";1/(3*r*c)
  if f<>0 then print tab(9);"Period  = ";1/f;"   Hi = ";(1/f)/3;"   Lo = ";((1/f)/3)*2
  if r<>0 and c<>0 then print tab(9);"Period  = ";3*r*c;"   Hi = ";r*c;"   Lo = ";2*r*c
  if t<>0 and c<>0 then print tab(9);"R1 & R2 = ";t/(3*c)
  if f<>0 and c<>0 then print tab(9);"R1 & R2 = ";(1/f)/(3*c)
  if t<>0 and r<>0 then print tab(9);"C1      = ";t/(3*r)
  if f<>0 and r<>0 then print tab(9);"C1      = ";(1/f)/(3*r)
  print:input"        Quit   ? ";q$:if left$(q$,1)="Y" or left$(q$,1)="y" then end
goto [init]