Talk:Potentiometer

Logarithmic taper definition

This results in a device where output voltage is a logarithmic function of the slider position.

Isn't this backwards? Methinks the output voltage is an exponential function of the slider position. Perhaps you could say that the slider position is a logarithmic function of the output voltage. ScottBurson (talk) 20:21, 10 July 2012 (UTC)

Adding difference in *function* between a potentiometer and rheostat

I would argue there is quite a bit of confusion and ambiguity as to the difference between potentiometers and rheostats in the general public (including myself until recently); enough to merit an explanation. This article only briefly states that there is a "trick" to using a potentiometer as a rheostat by wiring in a particular way - which in itself doesn't clarify much.

I'm proposing to add adding a paragraph about the difference in function between the two electric devices. Briefly: potentiometers allow full scaling of source voltage, from 100% to 0; rheostats are true variable resistors and are used mainly to reduce the current in a circuit by absorbing the excess energy.

And likewise it would be wise to add a similar paragraph in the Rheostat article, or at least link from there to the aforementioned one.

Do you agree? Any comments? (Mike002 (talk) 10:57, 17 March 2013 (UTC))

Convention for direction of travel

Is there a convention for showing direction of travel on the schematic? TINA-TI shows a dot for the "0%" end, for instance, while others show an arrow, but what does the arrow signify? https://xdissent.github.io/monowave-eagle/images/Potentiometers-symbol-POTENTIOMETER.png — Preceding unsigned comment added by 71.167.68.199 (talk) 20:44, 30 December 2014 (UTC)

Generally, a 3 port potentiometer's 0% end depends on how it is wired, although if it is mechanically coupled with an on/off switch on one end, it would matter, and that might be what the dot is for. I'm not sure what the extra arrow is for. ssd (talk) 12:14, 12 January 2015 (UTC)

Light dimmers

I have a quibble with the line " Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load.". Light dimmer switches are quite common. They also commonly fail. I've gone through at least a dozen of them. They generally burn out within a year of use. I've had many types, rotary dial, slide bar, rocker switch and push-button and they all fail. Somebody please invent one that doesn't. Ealtram (talk) 08:50, 12 November 2017 (UTC)

What are you buying, exactly? The common hardware store light dimmer uses a triac on a heat sink. The lamp current doesn't flow through the potentiometer, instead the adjustable knob controls the firing angle of the triac. I would be astonished if you can actually buy a plain potentiometer (simple variable resistor) labelled for use as a light dimmer in 2017! It would be enormous - something to control a 100 watt bulb I would expect would be the size of a coffee can or thereabouts. This is not the help desk but there's something going wrong if your triac dimmers don't last a long time; perhaps overload or something odd on the circuit? --Wtshymanski (talk) 16:49, 12 November 2017 (UTC)

Zero degree turn Membrane Potentiometers

On the 2nd last sentence of the first paragraph of Membrane Potentiometers is the following written: "... and the rotary versions range from 0° to multiple full turns, with each having a height of 0.5 mm."

Can someone explain to me what the point of a rotary potentiometer with a turning range of 0 degree is? Wouldn't it just have a fixed resistance then? And if that's the case, shouldn't this be corrected so that it mentions a more practical minimum turning range?

That's odd. It's also difficult to see hou you could do a multiple-turn pot with this technology. I've edited to conform the paragraph to the ref that supports it. Degree specification is replaced with a diameter specification. ~Kvng (talk) 15:38, 6 June 2020 (UTC)

Carbon Pile Rheostat

The Carbon Pile Rheostat has a long and illustrious history in the laboratory as the controlling mechanism for low voltage, high amperage ultra-high-temperature graphite resistance furnaces. https://patents.google.com/patent/US1543083A/en 2600:1700:6AE5:2510:0:0:0:40 (talk) 00:04, 27 October 2024 (UTC)