Light sensitivity of silicon strain gauges

The response of typical, commercial, silicon strain gauges exposed to a high intensity xenon flash source has been measured. Photovoltages are developed at the metal-semiconductor contacts and there is also a modulation of bulk conductivity. This conductivity change is of opposite sign for p-type and n-type gauges, and is due to a combination of thermal and optical effects. These results are a precautionary reminder that the magnitude of the response may be significant in some applications.