Triaxial Holocaust
I currently own tree instruments with triaxial BNC ports and no cables or connectors. A 601 electrometer, a 617 electrometer and a 224 current source. All with the old 2 lug triaxial connector.
I need at least 2 triaxial cables with BNC connectors. Something like the POMONA 4725.
The question is how not to spend a fortune. Each cable costs about US$115.
Another disadvantage is that the alligator clips are too big and cannot easily pass through a cable gland. This is important since most low level measurements take place in Faraday cages.
Also the 2-lug BNC connector means that the cable will not be usable with any newer devices with 3-lug connectors I may acquire in the future.
To build a cable from scratch is not much cheaper either. The triaxial plug with the lowest price on Digi-Key is the 3-lug PL75-47 and costs US$23.45. The 2-lug version PL74-47 costs 10 dollars more. At the time of writing the classic triaxial cable BELDEN 9222 cannot be found at a reasonable price in small quantities although at 30m (100 ft) it costs about US$3 per meter.
In the end I decided to file down a lug from each instrument and go for a 3-lug cable. I ordered an assembled 3-lug triaxial cable (BU-P5223-60 US$109) and cut it in half to make two cables.
List of materials
Description | Part Number | Supplier |
---|---|---|
Cable | BU-P5223-60 | Digi-Key |
Alligator clip | CTM-30C | Digi-Key |
Cable gland | LAPP 53112010 | Reichelt |
EMC nut | LAPP 54110840 | Reichelt |