Tektronix P6015A, Instruction Manual

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In Detail
P6015A Instruction Manual
1–9
NOTE . Some oscilloscopes may misinterpret the 1000X attenuation
code. Contact your local Tektronix representative if you have
questions.
Probe Placement
CAUTION.
Probe placement can be critical in some applications.
To minimize Device-Under-Test circuit loading, the P6015A input
resistance is very large and input capacitance is very small. Small
changes in capacitance near the input resistor will affect the
accuracy of the measurement. These changes can result from placing
the probe tip near conductive surfaces. Changes in the input
capacitance will change the probe compensation, causing the leading
edge of pulses to overshoot or undershoot the true pulse amplitude.
The time constant will not be visible on shorter pulses where the
entire top of the measured waveform will appear to be the wrong
amplitude. Surfaces connected to the input signal will peak the
response, resulting in overshoot, while those that are static or
grounded will dampen the response, resulting in an undershoot.
To minimize the chance of changing the probe compensation, do not
allow the conductor, to which the probe is attached, to pass along the
side of the probe body. Keep the probe perpendicular to the attached
conductor or at the end of a dedicated test lead. If the test configura-
tion does not allow this, minimize the error by readjusting the probe
compensation by connecting the probe to the calibration generator
that closely duplicates the physical configuration used in the actual
measurement.