An analysis of the insulated-gate thin-film field-effect triode as a current limiter is presented, and a comparison between theory and experiment is made for samples with cadmium selenide as the semiconductor layer. The theoretical treatment involves the extension of the analysis of

junction type current limiters to the thin-film, insulated-gate, field-effect device. Although the insulated-gate devices are operable in either enhancement or depletion modes, the analysis applies only to depletion mode operation. Good correlation between predicted and experimental values is found. This provides strong evidence that depletion mode operation of the device involves the modulation of semiconductor conductivity through a field induced variation of the depth of the space charge region. The characteristics of vacuum deposited cadmium selenide current limiters are also described.