such as integrated circuits or microwave circuits this allows the use of active termination in a small custom designed probe circuit circuitry such as a receiver may also be envisioned within one of these probe tip adapters also other embodiments may construct the circuit substrate in shapes other than a disk for example in some embodiments it may be useful to notch or key the substrate to prevent any rotation within the probe tip adapter one use of this invention is shown in fig4 and fig5 fig4 shows a measuring instrument 408 using a 10 1 attenuating 50 u03c9 impedance probe 406 to measure a source within a 50 u03c9 transmission line 402 the 450 u03c9 resistor 404 is a discrete device contained within the probe tip this resistor is placed as close as possible to the probe tip fig5 is a schematic representation of the measurement configuration from fig4 the 450 u03c9 resistor 404 is shown in series with the 50 u03c9 impedance 506 of the probe the measuring instrument is connected at node 510 from this schematic the 10 1 attenuation is present from the voltage divider created by the 450 u03c9 resistor 404 and the 50 u03c9 impedance 506 the probe is connected to the signal source at node 508 and the terminating resistor of the signal source is shown.