A Low Cost, Portable Milli-Voltage Integrator
Owen E. Thompson, Grant L. Darkow, Mark Hulse · Journal of applied meteorology · 1965
An integrating device for totalizing the output of various transducers with respect to time is described. The device is battery operated and costs less than $150. The input span is adjustable from 6 to 100 millivolts and the zero point can be set anywhere in the span. The unit can detect changes in input voltage as low as 25 microvolts. An overall accuracy of 1% to 2% for sufficiently slowly varying inputs and from 3% to 5% for input variations with a period of the order of 1 minute or less is claimed.