I would like to ask if I can connect a differential probe and a coax wire through a tee connector to 1 channel of an oscilloscope, in order to take different DC measurements.

The connection topology is shown in the image below. The idea is to avoid connecting different types of probes in an automated environment to the equipment when testing the different types of DUT. Both DUTs will never be connected at the same time when testing is being conducted.

I wanted to know if the differential probe can be damaged if DUT1 is active and is outputting a 30VDC signal which is being measured using a coax line. coax line is referenced to the chassis ground whereas the differential probe is required to measure 500VDC signal. The differential probe that I am using is a Rigol model RPD1025.

enter image description here

  • \$\begingroup\$ What does the datasheet of the diff. probe say? I highly doubt that it can (is designed to) withstand 30 V at its output even if it can output 30 V itself. Why not, instead of a BNC-tee, use a (Coax) switch relay? I mean something like: rfparts.com/cx540d.html \$\endgroup\$ Commented Jun 26, 2020 at 15:56
  • \$\begingroup\$ Since the diff probe output is usually actively driven, even when it's not measuring stuff then it would interfere with DUT1 measurements. \$\endgroup\$
    – Aaron
    Commented Jun 26, 2020 at 15:57

1 Answer 1


Yes, it can be damaged or at least it will interfere with the DUT1 measuring. The differential probe has an operational amplifier at its end - coax driver THS3202 or similar opamp. It is intended to drive a coax with a load of 1M ohm an 20pF, not a voltage source. If you connect the voltage source at its output it could be damaged


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