73 Series Coaxial & Kelvin Probes

The 73 Series of coaxial probes are excellent for most low current applications. They are available in several styles that include coax with integrated mounting shank, single and dual (series resistor), and Kelvin dual SSMC connections. For lower cost of ownership  the 73CT Series replaceable coax tips for the 74CJ-APT-KS Series offers similar results.  (replacement tips found in this section)

Durable construction
Flexible designs
Custom bends
Custom tapers and radii

Series 73 Coaxial Probes are designed for low level signal probing to less than 10fA. The probe's single unit design is especially desirable for the best possible electrical characteristics; however, in applications that can tolerate slightly higher noise levels, APT's 74J/X series of probe holders with replaceable points achieve similar results. The Series 73 Coaxial Probe is also offered with optional Ground Plane, Kelvin and resister series/parallel configurations.

(*Contact APT for further specifications available for your particular application.)

The Model 73 Series Probes are constructed of microwave-quality components. The 50 Ohm semi-rigid cable consists of 8 mil tungsten wire forming the inner conductor and probe point, with isolation from the gold plated copper shield being achieved through the utilization a Teflon dielectric. The probe contact protrudes from the shielding by .150" to maintain low level signal noise to the probe. Probe point radii are electrochemically etched to 5µm or point size may be specified by the user. The connector is an industry standard SSMC, mounted in a brass mounting shank where it is attached to the coax.

The 73 Coaxial Probe can be ordered in various mounting configurations to allow compatibility with all major manufacturer's brands of micropositioners and/or probe holders.

(*Please specify micropositioners and test station being used. APT can recommend the proper configuration for your requirements.)

Optional Interface Cables
To complete your probing configuration, APT recommends the Model 76CPC-SSMC Coaxial Cable. This RG# 178B/U cable has a characteristic impedance of 50 ohms, 29 pf/ft, and attenuation of 0.29 db/ft at 400 MHz. The dielectric is Teflon. A high frequency sub miniature SSMC connector attaches to any of APT's coaxial probes or SSMC equipped probe holders, and a BNC connector terminates the cable.


(*There is a $50.00 USD Minimum Order, applies to all purchases.)


Replaceable Coaxial Probe for 74CJ and DCP-100 Series Probe Holders



Minimum quantity for "73CT-APTA Replaceable Coaxial Probe" is 5.

True Kelvin Probe Design with series resistor on one contact probe Features True Kelvin connection, each probe is connected to one SSMC connector,...

Features Low Current Design. Frequency range DC to 500 MHz. Can be ordered with ground plane probe (*additional charge). Standard .125"...

True Kelvin Probe Design Features True Kelvin connection, each probe is connected to one SSMC connector, the ground/guard is shared. Requires...

Features Easily converts to R&K probe head. Lower current resolution than OEM coax probe. Specifications Easy retro-fit to OEM...

Minimum quantity for "73-1002-RK Probe" is 1.

For all of you that have asked the question, Can the 73CT Series replaceable coax probe be resharpened? The answer is YES!  This is what you...

Minimum quantity for "73CT-APTA Coaxial Probe Resharpen" is 1.