A power limiter for limiting power provided to an electronic device. The power limiter includes a waveguide that receives an input signal to be sent to the electronic device, an LaCoO3 film formed to one side of the waveguide, an LaCoO3 film formed to an opposite side of the waveguide, a grounded element formed to one of the LaCoO3 films and a grounded element formed to the other LaCoO3 film. When the heat level in the LaCoO3 films is below a predetermined threshold, the LaCoO3 films are an insulator and the input signal propagates through the waveguide to the electronic device, and when the heat level in the LaCoO3 films goes above the threshold, the LaCoO3 films become conductive, and the input signal is shunted through the LaCoO3 films to the grounded elements.