The TRD-100A is a light measuring device that is designed especially for response time and flicker measurements. The TRD-100A uses a PMT based photo detector with microcontroller-based gain control, photopic filter, and collection optics. The TRD-100A provides an analog voltage output that represents the relative luminance of the display under test. The output can be coupled to data acquisition cards or digital oscilloscopes for measuring display flicker, response time, or contrast. The TRD-100A is available in standard and high speed versions with mounting configurations for stand-alone, FPM, or fiber-coupled applications.