An algorithm is presented that generates simplified symbolic expressio
ns for the small-signal characteristics of large analogue circuits. Th
e expressions are approximated while they are computed, so that only t
he most significant terms are generated which remain in the final expr
ession. This principle leads to dramatic savings in CPU time and memor
y compared to existing techniques, significantly increasing the maximu
m size of circuits that can be analysed. By taking into account a rang
e for the value of a circuit parameter rather than one single number t
he generated symbolic expressions are also generally valid.