Talk:Pearson–Anson effect

Camera flash unit
Would this be what was responsible for the behaviour of the flash indicator light on an old 110-film camera of mine (which took its last ever picture a few days ago -- no more film cartridges!)? Turn the flash on, nothing appears to happen for a while except the typical charging whine. Then, as it approaches readiness, the indicator (which certainly appeared to be a miniscule neon lamp) starts ramping up in brightness; then it suddenly extinguishes, and repeats this cycle at an increasing rate until it stabilises (at maybe 5-10Hz?) -- or you take a picture. 77.102.101.220 (talk) 20:06, 19 June 2010 (UTC)
 * No. Typically, a camera flash circuit consists of a transformer and transistor which are wired to form an oscillator.  The oscillator produces the audible whine and it generates the high voltage that charges an electrolytic capacitor, which provides the energy for the flash tube.  The neon bulb is connected across the capacitor and acts as a voltage regulator:  once the voltage across the capacitor reaches the breakdown voltage of the neon bulb, current flows through the bulb instead of charging the capacitor, so the bulb lights and the voltage across the capacitor remains constant (instead of continuing to increase).  If the neon bulb in your camera's flash unit doesn't light and stay lit, then either the oscillator is having trouble supplying high-voltage current or the capacitor is breaking down.  Cwkmail (talk) 07:08, 3 February 2013 (UTC)

Power supply claim
'It is interesting fact that, in this old-fashioned arrangement, the humble neon lamp performs all the functions of the contemporary electronic 555 timer plus flashing and without any need of power supply! That is why this circuit is named "elegant simplicity"[4]'

I'd love to know how this lamp is supposed to oscillate & light without a supply of power. Tabby (talk) 20:12, 15 March 2011 (UTC)
 * Anyway, I've completly remove the whole statement as it has no place in this article -- this is not a hobbyst page.212.77.163.106 (talk) 10:48, 25 May 2011 (UTC)Apass

Implementation inaccuracies
I would say that points A and B from the explanation are not the same as in the figure - in fact, point A should be the high level threshold while point B the low level threshold. I'll study a bit more in depth the explanation and correct if indeed is inaccurate.212.77.163.106 (talk) 10:53, 25 May 2011 (UTC)Apass


 * You are right. The picture needs some correction: when the voltage increases, there is a current jump from point A to C (C has to be exactly above A); when the voltage decreases, there is a current jump from point B to D (D has to be exactly under B). Circuit dreamer (talk, contribs, email) 11:39, 25 May 2011 (UTC)

The picture should represent a hysteresis cycle


The I–V curve shown on the picture is not related to the Pearson-Anson effect since it represents the linear mode of operation of a neon lamp driven by a constant current source or through a high enough resistance. An example of this case can be a 1-port neon lamp amplifier exploiting the negative differential resistance section AB of the curve (i.e., the operating point lies on and moves along this section).

Here we need a picture of an IV curve representing the bistable mode of operation of a neon lamp driven by a constant voltage source (a charged capacitor) with zero or low enough internal resistance. In this application, the picture should represent a closed hysteresis cycle ACBD with two vertical segments (AC and BD) and two pieces truncated from the shown curve (BC and AD).

So, my general conclusion about negative differential resistance manifestations is that these elements possess two different kinds of IV curves (without and with hysteresis) depending on the source internal resistance (more precisely, on the ratio between the two resistances). Circuit dreamer (talk, contribs, email) 14:58, 25 May 2011 (UTC)

Change name to Pearson-Anson oscillator?
The term "Pearson-Anson effect" apparently coined in the 1920s to describe the oscillator's operation, is obsolete, as far as I can tell. I suggest the article be moved to Pearson-Anson oscillator or Neon lamp oscillator. -- Chetvorno TALK 05:52, 16 May 2015 (UTC)
 * Oppose. Current name is fine. Google search was indifferent. Journal titles suggest PA pointed out more general characteristics. Glrx (talk) 22:31, 18 May 2015 (UTC)
 * I don't know much about it, but in a brief search the only Google hits I could find that weren't copied from this article were and .  I'm not suggesting we delete the term "Pearson-Anson effect" from the article, just make it a redirect.  It just seems to me "Pearson-Anson oscillator" (or "neon-lamp oscillator") is a more commonly-used term for the subject of this article  per WP:COMMONNAME. -- Chetvorno TALK 00:24, 19 May 2015 (UTC)
 * The early history suggests there is a "Pearson–Anson" effect and that effect was used to make an oscillator. That means the topic is more general than just the oscillator circuit or an oscillator made from a specific noble gas. Glrx (talk) 17:55, 22 May 2015 (UTC)
 * I'll take your word for it. -- Chetvorno TALK 21:21, 22 May 2015 (UTC)

Neon lamps have also been used to make noise generators.
Neon lamps have been used as noise generator components before diodes were available. — Preceding unsigned comment added by 178.1.179.101 (talk) 16:25, 27 February 2021 (UTC)


 * Interesting. Do you have some sources? --ChetvornoTALK 18:34, 27 February 2021 (UTC)