Plant Electro-tropism Question
A question arose during my Plant Electro-tropism presentation on 3/6/2015 about the voltage test schematic. The quick answer is the test setup for my 2 channel oscilloscope recordings came from a Tektronix Application Note called: Fundamentals of Floating Measurements and Isolated Input Oscilloscopes.
“A minus B” Measurements (Also known as the Pseudo-Differential Measurements)
The “A minus B” measurement technique allows the use of a conventional oscilloscope and its passive voltage probes to indirectly make floating measurements. One channel measures the “positive” test point and another channel measures the “negative” test point. Subtracting the second from first removes the voltage common to both test points in order to view the floating voltage that could not be measured directly. Oscilloscope channels must be set to the same volts/division; the probes should be matched to maximize common mode rejection ratio.
To watch the recording of the full talk, click here.