Identify Audio Taper Potentiometers

[RussellW]

I have some 50k ohm audio slide pots and I don't know which end to ground.
Can someone tell me about audio taper pots? If I put the slider in the center then what should the resistance be from center to ground and the resistance from center to the audio input terminal?
Is there a better way to determine the taper of a pot and identify the terminals?

Thanks,
Russell Williams

 

[richie00boy]

Turn it fully anti-clockwise. The two pins measuring very low resistance are the wiper and ground.

 

[RussellW]

Oops! Slide pots don't have a counter-clockwise.

RussellW

 

[MoodySteve]

If you put the slider exactly in the center, you should measure about 25kΩ between the 'center' (wiper) and ends (legs) if it's linear taper. I think that most slide pots have a linear taper.

If you measure significantly less (probably around 2kΩ) or more (probably around 45kΩ) than 25kΩ, then you probably have an audio taper (log taper) pot. Which one of those you measure depends on which 'leg' you use as reference.

 

[RussellW]

If I put the slider in the center then I measure (very roughly) 10k ohms to one terminal (to the slider) and 40k ohms to the other terminal. Which terminal should be grounded and which should be audio input?

Thank-you all for your help.
Russell W.

 

[Don Hills]

The 40K ohms end should be grounded. Resistance changes more rapidly at the "grounded" end of the pot, because of the log resistance law. (Actually, most "log" pots are just two different linear resistance tapers connected at about 1/3 up from the "ground" end.)

 

[RussellW]

Thank-you very much, Don Hills.
That is very interesting.
I had a slide rule once (log log decitrig) and I noticed that 3 was close to the middle.
Relating the audio curve of the ear's sensitivity to a log scale is mind boggling to me.
Thank-you so much for the help.
Russell Williams