A method and device for testing and burning-in semiconductor circuits. The frequency of the generated oscillating signal may be variable and may be calibrated by calibrating a delay associated with the delay cells. Impurities are removed from the salt using a system that includes a first working electrode, a counter electrode, and at least one reference electrode. End rail are positioned adjacent the ends of the deck. At least three audio waveform portions including a first portion of the audio waveform that exceeds a first predetermined threshold, a second portion of the audio waveform below the first predetermined threshold and above a second predetermined threshold, and a third portion of the audio waveform below the second predetermined threshold can be graphically distinguished. The controller can set the sensor exposure time to a first value in response to a determination by the motion detector that there is movement of the at least a portion of the object between adjacent frames.