Correct potentiometer for a small speaker.

[Midas]

I am trying to find the correct pot to act as a volume control for a 32 ohms and 0.25 watts speaker. Most pots I have tried have given me about a couple of mm rotation from max to min volume. Any help would be much appreciated.

 

[Harald Kapp]

Use fixed resistors to find the max resistance for an acceptable low volume. The value will be somewhere in the range 100 Ohm ... 330 Ohm. Once you know the max. resistance, find a pot with similar rating.

Or use one of those pots you've already tested. Find the position where the speaker volume is "off" to your ears. Measure the resistance of the pot from wiper to start in this position and select a pot with fitting resistance.

Harald

 

[Midas]

Hi Harald, thanks for the reply!

Apologies for my novice understanding of electronics. I have a resistor that provides me with the lowest acceptable volume. The resistor is brown, blue, brown, gold so rated at 160 Ohm? Would I be looking for a 200 Ohm pot?

How about this one? http://uk.farnell.com/vishay-spectrol/534b1201jlb/potentiometer-2w-200r/dp/1144787

 

[CDRIVE]

Nurse call patient handsets employ 32 Ohm speakers. I've seen 500Ω and 1KΩ pots used in them, depending on the manufacturer. I know that 1KΩ seems high for this but it is what it is.

Chris

 

[BobK]

That pot is outrageously expensive, probably because it is 2W. A standard 1/2 W pot would do for you.

bob

 

[Raven Luni]

Sounds like the pots youve tried are too high in value. Use a parallel resistor to lower the effective range. It wont be linear but does that matter?

 

[Midas]

Used a 1K log pot, worked perfectly.
http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1141608

Excellent, friendly community. Thanks for all your help, especially on my first post!