Talk:Π pad

Pads
Pads (L-pads, T-pads, pi-pads, et.al.) are used for AC signals in the AF (audio) range and are not limited to RF applications. This article appears to be too narowly scoped.

Terminology
The article says "The voltage transfer function, A, is,


 * $$A = \frac{V_\mathrm {in}}{V_\mathrm {out}}$$

While the inverse of this is the loss, L, of the attenuator,


 * $$L = \frac{V_\mathrm {out}}{V_\mathrm {in}}$$

The value of attenuation is normally marked on the attenuator as its loss, LdB, in decibels (dB). The relationship with L is;


 * $$L_\mathrm{dB} = 20 \log L \,\!$$

Popular values of attenuator are 3dB, 6dB, 10dB, 20dB and 40dB.

"

I think that there is a contradiction there. If L = Vout/Vin then L < 1 and 20 log (L) < 0 which is inconsistant with popular values being positive numbers.

With attenuators, I expect gain to be less than 1 and loss to be greater than 1 and 20 log (L) to be positive.

Naturally then, if A is the inverse of L then the definition of A needs be inverted also.

So, I would change this to


 * $$A = \frac{V_\mathrm {out}}{V_\mathrm {in}}$$

and
 * $$L = \frac{V_\mathrm {in}}{V_\mathrm {out}}$$

Constant314 (talk) 00:50, 15 December 2010 (UTC)

Hyphen in title?
Sources aren't consistent, but the hyphen makes no sense. How about we change it to just Π pad, parallel to L pad? Dicklyon (talk) 02:13, 5 January 2011 (UTC)
 * Fine with me. Constant314 (talk) 04:10, 6 January 2011 (UTC)
 * Hearing no objections, moved this one and T pad, with help of admin (see below). Dicklyon (talk) 00:51, 7 January 2011 (UTC)

Requested move

 * The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 

The result of the move request was: page moved.  Sp in ni ng  Spark  00:31, 7 January 2011 (UTC)

Π-pad → Π pad — The noun form of a compound does not generally carry a hyphen. To make this article consistent with L pad and T pad, we should move it. Sources are mixed on this, but nobody has objected to my proposal (section above on article talk page). But Π pad is on the MediaWiki_talk:Titleblacklist, so I wasn't able to move it. --Dicklyon (talk) 04:00, 6 January 2011 (UTC)


 * Alternate use instead pi pad. BTW, why is this capitalized? Isn't it &pi; instead of &Pi; ? 64.229.103.44 (talk) 05:09, 6 January 2011 (UTC)


 * I was going to stay out of this, but now it looks like you need an admin to do the move, so convince me first before I try to do it. WP:HYPHEN is in favour of hyphenating nominal groups where this aids clarity to non-technical readers.  It may well not be clear to a lay reader here that the phrase is to be read as a compound.  The argument that this is inconsistent with L pad does not really count, that has only just been moved, a better consistency comparison is to a similar situation with beam cross-sections: I-beam, T-beam, H-beam.  There is also O-ring and T-bar.  The capitalisation of Π is for consistency with other circuits and because the straight lines of the capital form better represent the circuit topology.  Sp in ni  ng  Spark  11:05, 6 January 2011 (UTC)


 * I was upfront about the fact that sources differ on this; the L pad article has never had a hyphen, and a reconciliation seemed in order, so I had to pick one. Some book searches, like this one and this one, suggested that these are more common without a hyphen, and to me that was the logical way.  But it's hard to search for the pi without spelling it out; searches without it are more mixed, like this one.  In my experience, there are a minority of books that respect the English convention of hyphenating compound nouns when used as adjectives, and not otherwise, and a majority of books that are willy-nilly and seem to not be based on any style guide.  In general, I try to move wikipedia to be more like the former.


 * The thing you linked about nominal groups is pretty much consistest with what I have been taught: "a hyphen is particularly useful in long nominal groups (noun phrases) where non-experts are part of the readership, such as in Wikipedia's scientific articles: gas-phase reaction dynamics." Except that I'd express it differently; in nominal groups that include a noun phrase ("gas phase") used as an adjective, a hyphen is used in that noun phase.  Hence "T pad" and "T-pad schematic".  There is no example there, and no guide that I know of, that recommends a hyphen in a noun phrase used as a noun.  The "I-beam" example is an interesting exception, but is the conventional use in that field.  I don't see the same convention in electrical works.  They generally do "bridged-T pad" right, but mix up the rest.


 * Anyway, no editor objected to my proposal, which is now partly done, and on which I didn't expect to run into a problem, so how about helping to finish it?  Dicklyon (talk) 19:21, 6 January 2011 (UTC)
 * Ok, I moved it for consistency. Still don't really agree, but I'm not going to start a fight to have the others changed. Btw, my bad on L pad, I meant T pad of course.  Sp in ni  ng  Spark  00:31, 7 January 2011 (UTC)
 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.