SPICE Online

 General form:

     .TF OUTVAR INSRC

 Examples:

     .TF V(5, 3) VIN
     .TF I(VLOAD) VIN

      The TF line defines the small-signal output  and  input
 for  the  dc  small-signal  analysis.   OUTVAR is the small-
 signal output variable and INSRC is the  small-signal  input
 source.   If  this  line  is included, SPICE computes the dc
 small-signal value of the transfer function  (output/input),
 input  resistance,  and  output  resistance.   For the first
 example, SPICE would compute the ratio of V(5,  3)  to  VIN,
 the  small-signal  input  resistance  at VIN, and the small-
 signal output resistance measured across nodes 5 and 3.