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Archive 1 | Archive 2 |
clarify linear movement vs linear taper —Preceding unsigned comment added by Omegatron ( talk • contribs) 12:00, 1 September 2004
Calling a potentiometer a transducer is a long stretch. A potentiometer is a variable resistor. A resistor is a passive device and clearly not a transducer. A transducer converts one form of energy into another. At best, a potentiometer can be used as a sensor, but turning it does not generate energy. A pot could be part of a transducer circuit, but all by itself, it doesn't look like a transducer to me. -- ssd 04:56, 9 Mar 2005 (UTC)
pot is a slang term, and abbreviation for potentiometer, and as such, does not belong in an article like this. Use of the term potentiometer for anything else other than a variable resistor is archaic, and thus it is proper to use the term for this use now. -- ssd 20:40, 7 August 2005 (UTC)
I don't think a disambiguation page is necessary, especially since the derivation of the modern usage is based on the archaic meaning. I think it should be enough to include both meanings in the same article. It really isn't two different meanings, more like a shift in meaning, as the newer device was a part of the older device. -- ssd 23:01, 7 August 2005 (UTC)
On re-reading the article, I think it is a bit disorganized. The historical meaning is mentioned in two different places, and the material for rheostat is also a bit scattered through the article. It might be nice if someone (who can write better than me) rearranged it slightly. :) -- ssd 23:10, 7 August 2005 (UTC)
http://physics.kenyon.edu/EarlyApparatus/Electrical_Measurements/Potentiometer/Potentiometer.html http://chem.ch.huji.ac.il/~eugeniik/instruments/test/resistances.htm Light current 04:26, 10 August 2005 (UTC)
Ok FIRST we have the intro which has brief defns of both the 'original' potentiometer (the one used for measureing voltages) AND the 'modern' potentiometer.
THEN we have a heading 'Orignal Potentiometer' and do the description of that. Its already there under 'historical'
THEN we do the modern pot under the heading 'Modern Potentiometers' with its different types, applications, method of operation etc.
Now, how does that sound to every one??? Please lets agree on something:-))) Light current 02:49, 8 August 2005 (UTC)
Can we have some more comments apart from O'tron please, please? Light current 03:09, 8 August 2005 (UTC)
I have twice tried to edit this page within 6 hrs and the edits do not go through-the page is the same as the previous version. Is this page locked or only locked for me. Can someone else try and see if they can edit it? Or is there another explanation?? Light current 07:07, 8 August 2005 (UTC)
This page is not as I had attempted to edit it . Please ignore last edit comment saying that this is new layout .Its not- its the old one. Light current 07:12, 8 August 2005 (UTC)
Why are we keeping the comment on Varistors in here? THis page is complicated enough as it is and a varistor in Nothing to do with pots (not that I ve heard of). Can we remove it please without tantrums & tears??? Comments please Light current 02:19, 9 August 2005 (UTC)
There are many things that are NOT potentiometers, but we do not mention those do we? (thank God). Unfortunately, this is the way articles get confused(by irrelevant additions). If someone wants to mention varistor, it should be in a page on resistors as a special type. Just cos the word may sound remotely similar(both words have a 't' and an 'r' at the end) does not mean that they have to be differentiated here. I vote this entry is moved to resistors. Light current 12:03, 9 August 2005 (UTC)
Just following your example, O. Anyway we are not wasting electrons. See the page on capacitor operation. I never said it was long but it will be when I have added all the omissions! Light current 13:10, 9 August 2005 (UTC)
From your last comment ,O, it seems that you may be thinking that a 'varistor' has something to do with 'variable resistor'. It is NOT a user variable resistor (like a pot). It is in fact a voltage variable resistor and usually operates on semiconductor principles giving a non linear resistance against applied voltage. It is not a very good name for the device, I admit, but we are stuck with that. It is therfore completely out of place on the Potentiometer page. Lets move it to the resistor page where it would fit better(not perfectly, but better). I once again refer you to Uncle Albert's maxim :-) Light current 13:27, 9 August 2005 (UTC)
Keep calm., O. You know its not good for your blood pressure to get too excited!!(HAL: Take stress pill Dave..). In this case, since the term 'varistor' has a link ,appears in braces, etc I am happy(ish) to let it remain. BTW I didnt say it was a 'common misunderstanding' , I just sain that you appeared to be confused by the term.:-) Light current 17:38, 9 August 2005 (UTC)
Seems to be some gobbbledegook left in final para . I dont know what it means. Does any one have an input B4 I attempt to make it make sense? Light current 18:45, 11 August 2005 (UTC)
Yes I think your description of theory is more than adequate. Nice job! :) Light current 00:55, 12 August 2005 (UTC)
Rheostats are constructed differently than pots, and number of terminals the same in both. I have removed the incorrect information and added an external link describing rheostats. A picture of one here would be nice. -- ssd 18:45, 8 January 2006 (UTC)
So confusing. The article currently says one thing while this link says another, and I can't find any other info anywhere. — Omegatron 20:53, 19 January 2006 (UTC)
-- Light current 15:46, 21 February 2006 (UTC)
Well, it's 2006; not 1975. The link above says that there are different codes for now than there were in the past. Assuming you got the CW → log/CCW → antilog right, yours is even different from the "old" system mentioned:
Taper | Old Code | New Code | Alternate |
---|---|---|---|
Linear | A | B | LIN |
Log (Audio) | C | A | LOG |
Antilog | F | N/A | N/A |
Who do we believe? — Omegatron 19:20, 21 February 2006 (UTC)
Potentiometers are not used to control high-power devices, such as electric stoves, because of resistive losses, which limit the current-carrying capacity. Typically a pot will be used to regulate a higher power device by controlling the gain of a transistor or other device.
Controlling the transistor's gain by a resistor in order to conserve power is a nosense. AFAIK, the transistors are the variable (transient) resistors. Their resistance is controlled by the base current. Therefore, the techniques like PWM are preferred in the power lines for steppig down the voltage over the Linear Regulators just because of this reason. PWM means a switching mode of transistor (ON/OFF) whereas the linear regulator dissipiates the power resistively. You can adjust the PWM resistively, indeed. -- Javalenok 08:45, 9 February 2006 (UTC)
What sort of physical taper would you use on the resistive element to get a logarithmic variation of output voltage with shaft angle (assuming constant input voltage) ?-- Light current 16:08, 21 February 2006 (UTC)
Dont think so! If o/p voltage varies with (position)^2 as it would with a linearly tapering track, you would get a non linear relatinship between o/p and shaft angle. That is: O/P is propl to (x.y) where both and x and y depend on shaft angle. Get it? So how would you get a log o/p?-- Light current 22:17, 21 February 2006 (UTC)
Or, to put it another way, since o/p voltage is a linear function of your R2, then R2 must vary logarithmically with shaft angle to get a logarithmic variation of output voltage.
So this implies that a linear function multplied by a log function is a log function (correct I think). But if the pot had a proper linear taper of X sect, we would get, at the output, a voltage that was a function of the square of shaft angle (or displacement along the resistive track). Interesting!-- Light current 06:03, 22 February 2006 (UTC)
Do we really need to mention these switches as thay have nothing to do with the operation of the pot as such?-- Light current 22:05, 4 March 2006 (UTC)
I disagree! 8-) I will remove refs to such ASAP-- Light current 21:08, 1 August 2006 (UTC)
Looks as tho' we are arguing over nothing 8-)). I can see no ref to switches on this page. BTW 'O' on a personal note, how are you keeping? -- Light current 22:21, 1 August 2006 (UTC)
Well to be quite fair 'O', my notice (above) stood unreplied to 5 months. It looked like no one was bothered! 8-|-- Light current 15:19, 2 August 2006 (UTC)
I have re inserted a ref to pots being available with switches although this was already mentioned in the context of 'on-off' switches being combined with vol controls in consumer equipmnet. Happy?-- Light current 15:44, 2 August 2006 (UTC)
Quite possibly. Im feeling a bit groggy today. ill investigate -- Light current 17:48, 2 August 2006 (UTC)
Looks like I did revert to an older version. Apologies! This should now be the correct version with the switches mentioned-- Light current 17:58, 2 August 2006 (UTC)
Wasn't the zigzag replaced aith a box about two decades ago? Just zis Guy you know? 22:10, 12 April 2006 (UTC)
Split into modern pots and old fashioned potentiometers (measuring instruments) ? 8-|-- Light current 02:09, 11 June 2006 (UTC)
-- Light current 22:01, 21 June 2006 (UTC)
Is no one bothered about splitting the page just yet? Ill go with the consensus.-- Light current 12:48, 26 June 2006 (UTC)
This split was done on June 26, 2008. Greensburger ( talk) 16:47, 20 June 2009 (UTC)
I accessed article for description of types of element ie carbon, conductive plastic etc and include pros and cons. This article would benefit from including such information. Richard 02:22, 30 June 2006 (UTC)
I came here (as a reader) from Weatstone Bridge looking for a comparison between the wheatstone bridge as described in Wikipedia and the original use of the potentiometer. The present article describes the measuring use of the potentiometer via a series of variants, the first of which is the "Constant current". Understanding all of them depends on understanding the first. In "Constant current", there is verbiage that appears intended to describe the circuit, but a diagram would make it clear. Jack Waugh 17:58, 21 September 2006 (UTC)
the basic operation is that of voltage dividing.
rheostats were used at the beginning of electricity 1890s -- transistors were starting to be used in the mid1950s, after manufacturers learned how to make them with consistent characteristics.
the picture of the rheostat shows part of a toroid, over an insulated core -- —The preceding unsigned comment was added by Cem BSEE ( talk • contribs) 14:41, 29 December 2006 (UTC).
Clarify use of potentiometer as tone control. A resistor(eg pot) on its own has no effect on 'tone' (ie frequency response); it is only when used with a capacitor (or theoretically an inductor), that it can affect the tone of an audio signal.
—Preceding unsigned comment added by 203.20.101.202 ( talk • contribs) 00:57, 4 October 2006
Sorry if I'm not doing things properly, but this article nagged me. The mention of a rheostat is too brief and seems fairly inaccurate. The rheostat is used to adjust the current in a circuit and these circuits can be low powered (low voltage and low current). Typically, a rheostat is a potentiometer with the wiper tied to one end. They were typically two terminal devices and when they had three, two were shorted. These were very popular at one time and you would have seen them in communication circuits, including stereos. The POWER rheostat was used in larger applications where much power was to be dissipated through the resistor (hence the name "POWER"). There were also applications for reducing voltage using power potentiometers. Some old transformer winding machines had power rheostats to control the motor speed. The rheostat and potentiometer had different schematic symbols too. Remember, in the old days they did not care about conserving energy or saving the environment. Who really cared if a resistor was used to waste power? It did what it had to do and transistors were still fairly new and expensive. So, rheostat has all the mechanics of a potentiometer, except it is a variable resistive load. It does not have to be a resistive wire element, it can be carbon. It can be logarythmic, tapered or linear too! ~DP 12/11/2006 —Preceding unsigned comment added by Danpeddle ( talk • contribs) 01:51, 12 December 2006
These [2] are examples of what I call a "string pot". This device consists of a linear multi-turn potentionmeter attached to a spring-loaded spool of stainless-steel wire. As you unreel the wire, the spring loaded spool turns the potentiometer which results in a varying output voltage. There is no electrical connection to the wire. It is misleading to call the wire "resistance wire" as the resistance of the wire is uncontrolled and there is no reason why a string pot couldn't be make with a non-conductive material instead of stainless-steel wire. If I should leave "resistance wire" in the article, please comment here or on User talk: Sagsaw Sagsaw 17:47, 29 December 2006 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 |
clarify linear movement vs linear taper —Preceding unsigned comment added by Omegatron ( talk • contribs) 12:00, 1 September 2004
Calling a potentiometer a transducer is a long stretch. A potentiometer is a variable resistor. A resistor is a passive device and clearly not a transducer. A transducer converts one form of energy into another. At best, a potentiometer can be used as a sensor, but turning it does not generate energy. A pot could be part of a transducer circuit, but all by itself, it doesn't look like a transducer to me. -- ssd 04:56, 9 Mar 2005 (UTC)
pot is a slang term, and abbreviation for potentiometer, and as such, does not belong in an article like this. Use of the term potentiometer for anything else other than a variable resistor is archaic, and thus it is proper to use the term for this use now. -- ssd 20:40, 7 August 2005 (UTC)
I don't think a disambiguation page is necessary, especially since the derivation of the modern usage is based on the archaic meaning. I think it should be enough to include both meanings in the same article. It really isn't two different meanings, more like a shift in meaning, as the newer device was a part of the older device. -- ssd 23:01, 7 August 2005 (UTC)
On re-reading the article, I think it is a bit disorganized. The historical meaning is mentioned in two different places, and the material for rheostat is also a bit scattered through the article. It might be nice if someone (who can write better than me) rearranged it slightly. :) -- ssd 23:10, 7 August 2005 (UTC)
http://physics.kenyon.edu/EarlyApparatus/Electrical_Measurements/Potentiometer/Potentiometer.html http://chem.ch.huji.ac.il/~eugeniik/instruments/test/resistances.htm Light current 04:26, 10 August 2005 (UTC)
Ok FIRST we have the intro which has brief defns of both the 'original' potentiometer (the one used for measureing voltages) AND the 'modern' potentiometer.
THEN we have a heading 'Orignal Potentiometer' and do the description of that. Its already there under 'historical'
THEN we do the modern pot under the heading 'Modern Potentiometers' with its different types, applications, method of operation etc.
Now, how does that sound to every one??? Please lets agree on something:-))) Light current 02:49, 8 August 2005 (UTC)
Can we have some more comments apart from O'tron please, please? Light current 03:09, 8 August 2005 (UTC)
I have twice tried to edit this page within 6 hrs and the edits do not go through-the page is the same as the previous version. Is this page locked or only locked for me. Can someone else try and see if they can edit it? Or is there another explanation?? Light current 07:07, 8 August 2005 (UTC)
This page is not as I had attempted to edit it . Please ignore last edit comment saying that this is new layout .Its not- its the old one. Light current 07:12, 8 August 2005 (UTC)
Why are we keeping the comment on Varistors in here? THis page is complicated enough as it is and a varistor in Nothing to do with pots (not that I ve heard of). Can we remove it please without tantrums & tears??? Comments please Light current 02:19, 9 August 2005 (UTC)
There are many things that are NOT potentiometers, but we do not mention those do we? (thank God). Unfortunately, this is the way articles get confused(by irrelevant additions). If someone wants to mention varistor, it should be in a page on resistors as a special type. Just cos the word may sound remotely similar(both words have a 't' and an 'r' at the end) does not mean that they have to be differentiated here. I vote this entry is moved to resistors. Light current 12:03, 9 August 2005 (UTC)
Just following your example, O. Anyway we are not wasting electrons. See the page on capacitor operation. I never said it was long but it will be when I have added all the omissions! Light current 13:10, 9 August 2005 (UTC)
From your last comment ,O, it seems that you may be thinking that a 'varistor' has something to do with 'variable resistor'. It is NOT a user variable resistor (like a pot). It is in fact a voltage variable resistor and usually operates on semiconductor principles giving a non linear resistance against applied voltage. It is not a very good name for the device, I admit, but we are stuck with that. It is therfore completely out of place on the Potentiometer page. Lets move it to the resistor page where it would fit better(not perfectly, but better). I once again refer you to Uncle Albert's maxim :-) Light current 13:27, 9 August 2005 (UTC)
Keep calm., O. You know its not good for your blood pressure to get too excited!!(HAL: Take stress pill Dave..). In this case, since the term 'varistor' has a link ,appears in braces, etc I am happy(ish) to let it remain. BTW I didnt say it was a 'common misunderstanding' , I just sain that you appeared to be confused by the term.:-) Light current 17:38, 9 August 2005 (UTC)
Seems to be some gobbbledegook left in final para . I dont know what it means. Does any one have an input B4 I attempt to make it make sense? Light current 18:45, 11 August 2005 (UTC)
Yes I think your description of theory is more than adequate. Nice job! :) Light current 00:55, 12 August 2005 (UTC)
Rheostats are constructed differently than pots, and number of terminals the same in both. I have removed the incorrect information and added an external link describing rheostats. A picture of one here would be nice. -- ssd 18:45, 8 January 2006 (UTC)
So confusing. The article currently says one thing while this link says another, and I can't find any other info anywhere. — Omegatron 20:53, 19 January 2006 (UTC)
-- Light current 15:46, 21 February 2006 (UTC)
Well, it's 2006; not 1975. The link above says that there are different codes for now than there were in the past. Assuming you got the CW → log/CCW → antilog right, yours is even different from the "old" system mentioned:
Taper | Old Code | New Code | Alternate |
---|---|---|---|
Linear | A | B | LIN |
Log (Audio) | C | A | LOG |
Antilog | F | N/A | N/A |
Who do we believe? — Omegatron 19:20, 21 February 2006 (UTC)
Potentiometers are not used to control high-power devices, such as electric stoves, because of resistive losses, which limit the current-carrying capacity. Typically a pot will be used to regulate a higher power device by controlling the gain of a transistor or other device.
Controlling the transistor's gain by a resistor in order to conserve power is a nosense. AFAIK, the transistors are the variable (transient) resistors. Their resistance is controlled by the base current. Therefore, the techniques like PWM are preferred in the power lines for steppig down the voltage over the Linear Regulators just because of this reason. PWM means a switching mode of transistor (ON/OFF) whereas the linear regulator dissipiates the power resistively. You can adjust the PWM resistively, indeed. -- Javalenok 08:45, 9 February 2006 (UTC)
What sort of physical taper would you use on the resistive element to get a logarithmic variation of output voltage with shaft angle (assuming constant input voltage) ?-- Light current 16:08, 21 February 2006 (UTC)
Dont think so! If o/p voltage varies with (position)^2 as it would with a linearly tapering track, you would get a non linear relatinship between o/p and shaft angle. That is: O/P is propl to (x.y) where both and x and y depend on shaft angle. Get it? So how would you get a log o/p?-- Light current 22:17, 21 February 2006 (UTC)
Or, to put it another way, since o/p voltage is a linear function of your R2, then R2 must vary logarithmically with shaft angle to get a logarithmic variation of output voltage.
So this implies that a linear function multplied by a log function is a log function (correct I think). But if the pot had a proper linear taper of X sect, we would get, at the output, a voltage that was a function of the square of shaft angle (or displacement along the resistive track). Interesting!-- Light current 06:03, 22 February 2006 (UTC)
Do we really need to mention these switches as thay have nothing to do with the operation of the pot as such?-- Light current 22:05, 4 March 2006 (UTC)
I disagree! 8-) I will remove refs to such ASAP-- Light current 21:08, 1 August 2006 (UTC)
Looks as tho' we are arguing over nothing 8-)). I can see no ref to switches on this page. BTW 'O' on a personal note, how are you keeping? -- Light current 22:21, 1 August 2006 (UTC)
Well to be quite fair 'O', my notice (above) stood unreplied to 5 months. It looked like no one was bothered! 8-|-- Light current 15:19, 2 August 2006 (UTC)
I have re inserted a ref to pots being available with switches although this was already mentioned in the context of 'on-off' switches being combined with vol controls in consumer equipmnet. Happy?-- Light current 15:44, 2 August 2006 (UTC)
Quite possibly. Im feeling a bit groggy today. ill investigate -- Light current 17:48, 2 August 2006 (UTC)
Looks like I did revert to an older version. Apologies! This should now be the correct version with the switches mentioned-- Light current 17:58, 2 August 2006 (UTC)
Wasn't the zigzag replaced aith a box about two decades ago? Just zis Guy you know? 22:10, 12 April 2006 (UTC)
Split into modern pots and old fashioned potentiometers (measuring instruments) ? 8-|-- Light current 02:09, 11 June 2006 (UTC)
-- Light current 22:01, 21 June 2006 (UTC)
Is no one bothered about splitting the page just yet? Ill go with the consensus.-- Light current 12:48, 26 June 2006 (UTC)
This split was done on June 26, 2008. Greensburger ( talk) 16:47, 20 June 2009 (UTC)
I accessed article for description of types of element ie carbon, conductive plastic etc and include pros and cons. This article would benefit from including such information. Richard 02:22, 30 June 2006 (UTC)
I came here (as a reader) from Weatstone Bridge looking for a comparison between the wheatstone bridge as described in Wikipedia and the original use of the potentiometer. The present article describes the measuring use of the potentiometer via a series of variants, the first of which is the "Constant current". Understanding all of them depends on understanding the first. In "Constant current", there is verbiage that appears intended to describe the circuit, but a diagram would make it clear. Jack Waugh 17:58, 21 September 2006 (UTC)
the basic operation is that of voltage dividing.
rheostats were used at the beginning of electricity 1890s -- transistors were starting to be used in the mid1950s, after manufacturers learned how to make them with consistent characteristics.
the picture of the rheostat shows part of a toroid, over an insulated core -- —The preceding unsigned comment was added by Cem BSEE ( talk • contribs) 14:41, 29 December 2006 (UTC).
Clarify use of potentiometer as tone control. A resistor(eg pot) on its own has no effect on 'tone' (ie frequency response); it is only when used with a capacitor (or theoretically an inductor), that it can affect the tone of an audio signal.
—Preceding unsigned comment added by 203.20.101.202 ( talk • contribs) 00:57, 4 October 2006
Sorry if I'm not doing things properly, but this article nagged me. The mention of a rheostat is too brief and seems fairly inaccurate. The rheostat is used to adjust the current in a circuit and these circuits can be low powered (low voltage and low current). Typically, a rheostat is a potentiometer with the wiper tied to one end. They were typically two terminal devices and when they had three, two were shorted. These were very popular at one time and you would have seen them in communication circuits, including stereos. The POWER rheostat was used in larger applications where much power was to be dissipated through the resistor (hence the name "POWER"). There were also applications for reducing voltage using power potentiometers. Some old transformer winding machines had power rheostats to control the motor speed. The rheostat and potentiometer had different schematic symbols too. Remember, in the old days they did not care about conserving energy or saving the environment. Who really cared if a resistor was used to waste power? It did what it had to do and transistors were still fairly new and expensive. So, rheostat has all the mechanics of a potentiometer, except it is a variable resistive load. It does not have to be a resistive wire element, it can be carbon. It can be logarythmic, tapered or linear too! ~DP 12/11/2006 —Preceding unsigned comment added by Danpeddle ( talk • contribs) 01:51, 12 December 2006
These [2] are examples of what I call a "string pot". This device consists of a linear multi-turn potentionmeter attached to a spring-loaded spool of stainless-steel wire. As you unreel the wire, the spring loaded spool turns the potentiometer which results in a varying output voltage. There is no electrical connection to the wire. It is misleading to call the wire "resistance wire" as the resistance of the wire is uncontrolled and there is no reason why a string pot couldn't be make with a non-conductive material instead of stainless-steel wire. If I should leave "resistance wire" in the article, please comment here or on User talk: Sagsaw Sagsaw 17:47, 29 December 2006 (UTC)