WordNet (r) 3.0 (2006):

circuitry
    n 1: electronic equipment consisting of a system of circuits

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "circuitry":
   amplifier circuit, astable circuit, back-to-back switching circuit,
   circling, circuition, circuitousness, circularity, circulation,
   circumambience, circumambiency, circumambulation, circumflexion,
   circumlocution, circummigration, circumnavigation,
   coupling circuit, deviance, deviancy, deviation, deviousness,
   digression, equivalent circuit, excursion, excursus,
   flip-flop circuit, gyre, gyring, indirection, meandering,
   microcircuit, monostable circuit, nonsinusoidal circuit, orbit,
   orbiting, printed circuit, rectifier circuit, roundaboutness,
   rounding, semiconductor circuit, spiral, spiraling,
   thermionic tube circuit, transistor circuit, turn, turning,
   wheeling