| dc.description.abstract | This abstract describes an instrument for the statistical study of the various analog parameters of a physical operation, which vary with time. The parameters may be, for example, voltage, pressure, volume, etc. A selected one of these parameters is converted by means of a transducer to an electrical voltage, which is proportional to the value of the parameter at all times. This voltage is continuously compared with a reference voltage of a selected magnitude, and means are provided in response to this comparison to record the accumulated time intervals during which the parameter voltage is different in a selected manner from the reference voltage. Means are also provided for determining the number of such times when the parameter voltage is different from the reference voltage, during a selected total time interval. By using a plurality of such systems each with a different reference voltage, statistical data can be accumulated in a simple and inexpensive manner. In an improved embodiment, the voltage comparator is designed to provide a hysteresis characteristic, in which it turns on at a given value of the variable and turns off at a lower or higher value of the variable. Also, in the use of an electrolytic cell to count pulses, the embodiment includes the design of an improved pulse shaper. Means are also provided for limiting the time duration of the entire test period and providing means to shut off power when the time limit is reached. | |
