Using RCA to read voltage

Question

I've connected an RCA cable to a device to read an analog voltage signal that's +/- 2.5V from what I can tell. The problem is that I need to somehow connect the other male RCA end with the computer in order to read the signal via program (LabVIEW to be specific), and I've connected a analog-to-digital converter (NI USB-6009) for that purpose.

Question: Is there an adapter that can make the male RCA into some kind of 2 or 3 wire that's pos/neg or pos/neg/gnd so that I can connect it to the converter? Or is it possible to strip the actual cable down (i.e. cut the RCA cable) and separate out the different components?

Answer 1

According to the NI USB-6009 specs, it can be driven either with a floating signal source or a grounded single-ended source. An RCA connector provides a two-terminal connection, preferably with the exposed shell grounded. See p. 12 of the manual for a diagram, most likely RSE on the lower left.

This depends, of course on your signal source: is it floating or single-ended? Be careful of ground loops and voltage limit, so you don't fry the PC and ADC.

Answer 2

This "adapter" should do. It certainly makes your RCA cable adapt to a 2+2 wire specification. After you've applied the "adapter", put some crimps on the ends. Some like to put sonder on the ends, but I avoid that as it is detrimental to proper contact, especially on higher voltages.

As for your specific of pos/neg/gnd on one of them, this becomes an issue, as RCA is a 2wire contact. What ground means in this setting can vary: It could be any shielding the cable might have, or it could be the negative lead.