Talk:Potentiometer/Archive 2

message: The reference to an early Edison patent for a carbon potentiometer in 1872 needs work.  Historical web sites such as www.tomedison.org/invent.html refer to Edison's 1872 invention of the "carbon rheostat" which consisted of powdered graphite in glass tubes that changed resistance by increasing and decreasing pressure on the graphite with a screw/knob.  Edison abandoned this because it was too sensitive to vibration.  I could not find his patent for this.  Edison got a US patent 131,334 titled "Rheotomes or Circuit-Directors" but this is for a selector switch, not a rheostat, although a simple modification could change the switch into a multi-tap potentiometer as was used in radio broadcasting studios and audio recording studios where they were called "pots".  In 1877, Edison revived the vibration-sensitive rheostat for use as a carbon (graphite) telephone transmitter.  On the web site edison.rutgers.edu/sernote3.htm near the bottom there is a reference to Edison's notebook entry for a "carbon rheostat" in 1873.  Rheostats using a screw/knob to vary current by varying pressure on graphite were used in power supplies for vacuum tube radios during the 1920's and 1930's and they were labeled rheostats. Greensburger 02:10, 5 January 2007 (UTC)
thread_title:  Rheostat/Rheotomes 

message: Remove the invalid redirection "Redirected from Potentiometric analysis" --208.114.161.196 15:50, 18 February 2007 (UTC)
thread_title:  Requested improvements 

message: "(...) a setting of 5 sounds half as loud as a setting of 10", it says in the Audio Control section about logarithmic pots. Shouldn't that be: "5 sounds half as loud as 6?". I don't know a lot of maths. Dafferson 23:10, 3 June 2007 (UTC)
thread_title:  Loudness 

message: Tell whats the difference between linear, tapered, and logarithmic types.  i am a electric engineer, and i sometimes rely on wikipedia to do my electronics!!  i consider this piece of article VERY important!! XU-engineer 21:35, 10 June 2007 (UTC)
thread_title:  Differences 

message: I would like a correction on digital pots. The statement "they allow small adjustments to be made to the circuit by software, instead of a mechanical adjustment." is not correct. It implies that you cannot control a digital pot any other way, when in fact, you can. We use them, but use an electronic interface that has no software or no firmware. It is very simple and some digital pots will allow and up/down switch. The serial ones can be interfaced electronically too and without software or firmware. Not all use I2C bus, many also use a simple two wire serial bus. So, I would suggest this be corrected. Danpeddle 04:38, 4 October 2007 (UTC)
thread_title:  Requests 

message: It seems their is too little understanding of what is a rheostat. You have stated a rheostat "is usually much larger, designed to handle much higher voltage and current" when comparing to a potentiometer. Please, understand what you are writing so the wiki world doesn't look so foolish! This is a statement that an uneducated novice would make. 
A rheostat is a two terminal variable resistor used to control current. It has one fixed end and one variable end (the wiper). They can be high power high voltage, low power low voltage or anything in between. They can also be linear in shape or any shape a potentiometer comes in. They can be linear taper, log taper, any other taper and even digital. 
A Potentiometer is a three terminal variable resistor used to control voltage (variable voltage divider). It has two fixed ends with a variable middle (the wiper). They can be high power high voltage, low power low voltage or anything in between. They can also be linear in shape or any shape a potentiometer comes in. They can be linear taper, log taper, any other taper and even digital. 
Basically, they are the same component, except the rheostat has either a wiper shorted to one fixed end or the second fixed end of a potentiometer is not connected to anything. Try it, take any potentiometer and short the wiper to one fixed end and you have a rheostat or do not connect the second fixed end in your circuit! Please note, that it is better practice to short the wiper to one fixed end of a potentiometer or purchase a rheostat.
BOTH a potentiometer and a rheostat can be seen as varying the resistance (depending on where the measurement is made). After all, they are VARIABLE resistors.
They are also represented slightly different schematically. And, speaking of schematic symbols, the rheostat actually has two; one that shows it's wiper connected to one end and one that shows an arrow THROUGH a resistor (no connection of the arrow to the fixed end)
Danpeddle 04:09, 4 October 2007 (UTC)
replies: text: OK, sounds good. You sound well qualified to update the article to make the distinction then. --Hooperbloob 22:04, 28 October 2007 (UTC)
replies: text: A rheostat is definitely a two-terminal device - the essence of the "potentiometer" is the variable voltage divider, three-terminal configuation. --Wtshymanski (talk) 16:11, 17 December 2007 (UTC)

text: It's how you use the device.  If you use one fixed end and take current out the slider, it's a rheostat.  If you use both fixed ends and use the slider as an adjustable voltage divider, it's a potentiometer. A rheostat is an adjustable resistance, a potentiometer is an adjustable voltage divider. Sometimes those who need a rheostat use a potentiometer and tie the slider and one fixed terminal together. IEEE Standard 100 is unusually useful in these defintions, and if it's good enough for the IEEE, it should be good enough for Wikipedia. I should fix the caption if it's misleading.  --Wtshymanski (talk) 15:45, 2 October 2008 (UTC)
thread_title:  Rheostat vs. Potentiometers 

message: I've removed the following text from the digital pot section, because there really isn't any tie in to this article.  A digital pot could be used to create a hybrid digital and analog control system, but nothing in the removed text really describes how a digital pot would be used in such a system or the advantages/disadvantages of using a digital pot in such a system. Sagsaw 18:20, 28 October 2007 (UTC)
thread_title: Digital pot section

message: I suggest merging the stub digital potentiometer into the "digital control" secton of the "potentiometer" article, until it grows large enough to need its own article.
(p.s.: When it does get big enough to split, remember to redirect Digitally controlled potentiometer to the appropriate place).
--68.0.124.33 (talk) 03:49, 7 July 2008 (UTC)
thread_title:  merge 

message: Ive found this on fender guitar amps.zdoes anyone know what it means?
                   megaarxidas
Unsigned contribution by  00:10, 11 May 2009
:Please post questions at WP:Reference desk/Science.  This page is for discussing improvements to the article. SpinningSpark 13:59, 12 May 2009 (UTC)
thread_title:  RV onpotentiometers what does it mean? 

message: Is up for deletion if anyone knows anything about it or can help determine whether it's a notable subject.  ChildofMidnight (talk) 06:24, 20 June 2009 (UTC)
thread_title: [[Pot mod]]

message: Other languages have a separate page for Rheostat, but in English it's just a redirect here.  Am I allowed to link the Rheostat redirect to the equivalent article in other languages? Flying fish (talk) 19:10, 2 August 2010 (UTC)
replies: text: Seems a reasonable thing to do to me. SpinningSpark 06:36, 3 August 2010 (UTC)
thread_title: Redirect

message: Wtshymanski, I puzzle out how to explain to you the difference between potentiometer and voltage divider. Well, let's try again... Potentiometer is the name of the "pure" unconnected element (a three-terminal resistor with a sliding contact) while voltage divider is the name of one possible application of this element where the input voltage is applied between the ends and the output voltage is taken between one end and the wiper. So, you may connect a potentiometer as a voltage divider but, for example, with the same success you may connect it as a current divider. For this purpose, ground the pot ends and connect a current source to the slider (note the slider is an input here while the ends are outputs!). By moving the slider you can change the proportion between the current flowing through the two legs. Does this potentiometer form a voltage divider as your source claims? No, it is not a voltage divider at all! It is something absolutely different; it is a current divider! Another similar application is to apply voltage to the wiper; think of this arrangement as of two complementary rheostats with a common point... That is why I have added this "...can form a voltage divider..." instead "...forms a voltage divider..." A potentiometer can be a voltage divider but it can be something else as well... Please, find a more reliable source for the definition. Circuit dreamer (talk, contribs, email) 22:23, 4 August 2010 (UTC)
replies: text: Perhaps because the literal meaning of the name potentiometer is a measured potential.  Current, unlike voltage, cannot be described as potential. SpinningSpark 10:31, 7 August 2010 (UTC)

text: This is just more POV and OR like we have seen before. It is good that you are no longer assigning the benefits of negative resistance to virtually every electronic circuit but it appears you have just embarked on some other taxonomy. I thought we had disabused you of all this. Zen-in (talk) 15:52, 7 August 2010 (UTC)
thread_title:  Is the potentiometer only a voltage divider?