12
Operating the Probe
Recommended Test Equipment
• Offset null zeroes the dc level at the output of the probe. The range of adjustment is
about ±4 mV.
• DC Reject Gain adjusts the gain of the dc reject circuit to accurately null the dc
component of an input signal. The range of adjustment is about ±0.5%.
Figure 1-5
1142A Front Panel
Equipment Needed
The following equipment is necessary for initial adjustment.
• 5 V power supply
• DVM that can measure 25 µV
•50 Ω BNC feedthrough terminator
• 01141-66504 test board
Equipment Setup
Use the following procedure to setup the differential probe system for initial adjustment.
CAUTION Do not exceed ±7 V when using the test board for this procedure. If the voltage is too
high, it will cause excessive power dissipation in the 50 Ω termination on the test board.
1 Use the probe setup procedure to set up the probe system.
2 Connect a 50 Ω BNC feedthrough terminator to the output of the probe.
3 Disconnect all accessories from the input of the probe.
4 Connect the DVM to measure the dc output of the probe at the 50 Ω load.
