Teledyne LeCroy AP033 - Manual (Page 14)

AP033 Active Differential Probe
8 922260-00 Rev A
Operation
CAUTION: The input circuits in the AP033 incorporate components that protect the probe
from damage resulting from electrostatic discharge (ESD). Keep in mind that this is an active probe,
and it should be handled carefully to avoid damage. When using the AP033, you are advised to take
precautions against potential instrument damage due to ESD.
Connecting the Probe to the Test Instrument
When using the AP033 Active Differential Probe with a Teledyne LeCroy Oscilloscope equipped
with ProBus, attach the probe output connector to the oscilloscope input connector. The
oscilloscope will recognize the probe, set the oscilloscope input termination to 50Ω, and activate
the probe control functions in the user interface.
To use the AP033 Active Differential Probe with instrumentation not equipped with a ProBus
interface, it is necessary to use the ADPPS Power Supply. Attach the ADPPS connector to the probe
output connector. The output connector of the ADPPS is a standard male BNC that can be directly
connected to another instrument. If necessary, the output of the ADPPS can be interconnected
with a 50 Ω coaxial cable. To minimize the effect of skin loss, this cable should be 1 m or less in
length. The AP033 Active Differential Probe is designed to drive a 50 Ω load. The gain will be
uncalibrated if the output is not correctly terminated. If you are using the probe with an instrument
with a high input impedance, place a 50 instrument input before attaching the ADPPS..
Connecting the Probe to the Test Circuit
At the probe tip, two inputs and a ground connection are available for connecting the probe to a
circuit under test. For accurate measurements, both the + and – inputs must always be connected
to the test circuit. The ground connection is optional. Positive voltages applied to the + input
relative to the – input will deflect the oscilloscope trace toward the top of the screen.
Positive voltages applied to the + input relative to the – input will deflect the oscilloscope trace
toward the top of the screen.
To maintain the high performance capability of the probe in measurement applications, user care
in connecting the probe to the test circuit. Increasing the parasitic capacitance or inductance in the
input paths may introduce a “ring,” or slow the rise time of fast signals. To minimize these effects,
use the shortest length possible when connecting the probe to the circuit under test. Input leads
that form a large loop area (even shielded coaxial cables) will pick up any radiated magnetic field
that passes through the loop, and may induce noise in the probe inputs. Because this signal will
appear as a differential mode signal, the probe’s common mode rejection will not remove it. You