Talk:Capacitive coupling

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How does capacitive coupling actually work if no current (inc displacement current) can flow between the plates?--Light current 23:46, 18 December 2005 (UTC)[reply]

In a DC circuit, it can't work. In an AC circuit, capacitors conduct by inducing voltages in their opposing plate. This is more useful for transmitting information than power. --ssd 23:24, 28 December 2005 (UTC)[reply]

The article previously said that inductive coupling "favoured the low-frequency component of a signal." This is not true. "Inductive coupling" is typically used to mean transformer coupling, which, like capactive coupling, is high-pass. 66.30.14.1 07:01, 21 March 2006 (UTC)[reply]

Isn't this the same thing as condenser coupling? -- Slowmover 17:10, 24 October 2006 (UTC)[reply]

Yes, but condenser is an obsolete term these days.

Atlant 17:38, 24 October 2006 (UTC)[reply]

Thanks. I'd never encountered the term condenser for capacitor before. Came across it because many stereo power amps from the 1970s/1980s have connections that are labelled that way, or have a switch to choose between "condenser" and "direct" coupling. Maybe this should be mentioned somewhere here, or in other relevant articles. Not being an expert, I leave it to someone else. -- Slowmover 20:10, 30 October 2006 (UTC)[reply]

I was looking for AC coupling, I got a redirection to here (Capacitive coupling). However, transformer coupling in another form of AC coupling and this is currently ignored. The solution might be to:

1. Write an article about AC coupling that covers both capacitive coupling and transformer coupling.

2. Write an article about transformer coupling and a small one about AC coupling that have links to the two of them.

There used to be a section about the use of capacitive coupling in digital circuits. It seemed to imply that you can use a capacitor as a level-shifter. There are cases where nominally "digital" signals end up getting AC-coupled (for example, when Ethernet couples stuff through the isolation transformers). There are even cases where you would AC-couple a signal with a capacitor; for example, I might take a small-amplitude clock, one that doesn't swing sufficiently positive to give a good logic HIGH, and cap-couple it symmetric about Vdd/2, to make better use of the available peak-to-peak swing. That's not a very common thing to do, though, and the discussion that I removed was just wrong. —The preceding unsigned comment was added by 66.30.10.35 (talk • contribs) 10:29, 4 December 2006 (UTC).[reply]

What is the reason for the cleanup tag? Please list suggestions or reasons here. Dicklyon 23:13, 19 February 2007 (UTC)[reply]

Is there merit to the description given here: http://www.counteractrust.com/capacitive%20coupling.htm Can this be added as a use of capacitive coupling? Pendragon39 (talk) 17:14, 9 October 2008 (UTC)[reply]

Touchscreens are one of the most prominently used consumer devices that (according to this article; reposted here) are based on this technology. I'm not qualified to confirm that claim, but if it is true, I would think that it should get a prominent mention in this article.Kmote (talk) 14:22, 9 October 2013 (UTC)[reply]

I seem to remember from my reading extensively about radio frequency circuits that capacitors were frequently used to 'isolate' some circuit components from interfering rf (radio frequency) currents often carried on the common +'ve power supply bus. This may no longer be an issue in an era of integrated circuits and digital signal processing but it certainly was in the analog era using vacuum tubes and much higher operating voltages. Every five tube AM radio would have a number of 'decoupling' capacitors and failure of any one could send the whole radio into oscillation or worse. Spyglasses 06:26, 7 August 2015 (UTC)

Yes, decoupling capacitors are still used extensively today to decouple one part of the system from another. The deleterious coupling between components usually occurs via shared power/ground planes. Adding capacitors makes the power/grounds somewhat locally independent of each other because of the close reservoir of stored energy. It is hard to build a decent sized capacitor on-die so the "decaps" are mainly either in the IC package or adjacent to the package footprint on the PCB. hth. SageGreenRider (talk) 11:20, 7 August 2015 (UTC)[reply]