Teledyne LeCroy AP034 - Manual (Page 28)

AP034 Active Differential Probe
22 922261-00 Rev A
Matching Procedure for ÷10 Plugs
The ÷10 and ÷20 Plug-on attenuators provided as standard accessories with the AP034 are
calibrated to match the specific probe they are shipped with. Individual probes will have small
variations in parasitic capacitance within the input circuits. To obtain maximum common mode
rejection performance, the attenuators are calibrated to match a specific probe during the
manufacturing process. In order to preserve the maximum Common Mode Rejection, do not
interchange external attenuators between probes.
The Plug-on AC coupling adapter is not matched to a specific probe and, therefore, does not need
to be matched when interchanged. If the ÷10 or ÷20 Plug-on attenuators become accidentally
mixed between probes, you can use the procedure listed below to restore the compensation
match. This adjustment does not affect any of the parameters in the warranted specifications.
Therefore, the required test equipment does not need to be calibrated.
NOTE: The AP033 and AP034 Active Differential Probes have different input capacitance. The

10
Plug-on attenuator supplied with model AP033 cannot be properly adjusted for use with model
AP034. Make sure that the attenuator is marked “AP034” before attempting this procedure.
Equipment Required
Test Oscilloscope
The oscilloscope must support ProBus. Otherwise use a non- ProBus oscilloscope and ADPPS
power supply.
Signal Source
Low frequency square wave: Frequency 50 Hz to 5 kHz, Amplitude 1 V to 10 V. The output
waveform must have a square corner and flat top with minimum overshoot suitable for adjusting
compensation. The generator should have trigger output, or use a BNC Tee connector and separate
BNC cable from the output to provide the trigger signal for the test oscilloscope.
Interconnect Cable
This is for connecting the output of the signal source to the probe. A BNC cable and a pair of small
alligator clips or “lead grabber” adapter (Pomona #3788) may be used. 0.025 in. (0.635 mm)
Square Pins (3 required). The pins from the header supplied in the probe accessory kit are suitable.
Tools
Flat bladed screwdriver, 0.040 in. (1 mm) wide
Adjustment Tool: 0.025 in. (0.635 mm) square head