Oxygen sensor having thin film electrolyte

Oxygen sensor incorporating a thin film electrolyte such as yttria stabilized zirconia sputtered onto a substrate produces an electrical signal in response to differences in oxygen partial pressures. The electrical signal changes rapidly enough for useful operation at temperatures which are substantially lower than those required by conventional oxygen sensors having a rigid, self-supporting thimble, tubular, or disc type electrolyte. For example, rapidly responding signals have been generated at temperatures below 200 DEG C whereas state of the art devices such as those used for sensing exhaust gases in automotive vehicles require temperatures higher than about 400 DEG C.