HBM Genesis GEN5i User Manual page 530

530
Figure D.14: Frequency response with 1X probe
Example: assume a voltage source with a 1 MΩ resistance and a 1X probe with
50 pF capacitance (a 1X probe by itself has no resistance). The universal
amplifier input has a 1 MΩ resistance and a 100 pF capacitance.
This yields a – 3dB point at:
= 1 / (6.28 x 500 E+3 x 150 E-12) ≈ 2 kHz
The loading due to the input impedance of the instrument and the probe
capacitance is twofold: resistive loading and capacitive loading.
The resistive loading actually reduces the voltage delivered to the instrument:
The effect of the capacitive loading is more complex and results in an
exponential response in the voltage:
GEN5i
Frequency
(EQ1)
(EQ2)
(EQ3)
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