The charging/discharging of a battery (1u to 30 mA) and remote voltage measurement is to be performed over 2 pairs of 2 m cable. In order to reduce picked up common mode noise I intend to use shielded twisted pair cable.

But I don't know which one to choose. There are several properties to consider.

The first is the gauge. This one is clear: the thicker, the better.

Somewhat more obscure are the types that listed i. e on Mouser: what is the real difference beetween those types?

Then there is insulation and jacket material. I am not sure whether I need to consider it in the first place?

And the last and most difficult is the shield itself.

I know that there are braided shield, which has lower resistance, and foil which has better coverage. But I can't decide what of that is more important (?)

Is there perhaps something else that has to be taken in account?

I would like to get anwsers disregarding whether you think I need shielding or not.

EDIT: this what I see if I attach oscilloscope probe to a 1.8 m unconnected unshielded cable:

Full signal:enter image description here

Bandlimited to see low frequency more clearly: enter image description here

First picture zoomed in time: enter image description here

  • \$\begingroup\$ Does the cable really matter for your signal bandwidth? Like the probes for those 6 1/2 digit multimeters uses neither shielded nor twisted cable for the probes and there's no problem of that ever. Are you sure the cable is the the bottleneck of your performance? Your application is not like hi-fi where $$ cable sounds better than $ cable, is it? \$\endgroup\$ Jun 19, 2017 at 2:58
  • \$\begingroup\$ This is precise DC measurement, so the bandwidth is ideally 0. So I try limit external disturbance as much as possible. \$\endgroup\$
    – Andrey Pro
    Jun 19, 2017 at 11:33
  • \$\begingroup\$ Whatever noise your cables will pick will necessarily be AC. Unless you're going to do 50 measurements per second, you'll hardly benefit from shielding. \$\endgroup\$ Jun 19, 2017 at 11:35
  • \$\begingroup\$ @Dmitry Grigoryev. In fact, I will. perhaps up to 100 per second \$\endgroup\$
    – Andrey Pro
    Jun 19, 2017 at 12:00
  • \$\begingroup\$ @AndreyPro Then I suggest you get shielded cables for mains-powered appliances near your setup. Shields are much more effective when placed near the source. \$\endgroup\$ Jun 19, 2017 at 12:05


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.