why are slider-pots so much harder to find than rotary pots?

tangramkid

i've been trying for a while to find a source of slider-pots, preferably small ones, and i've only found some at a local surplus place (got lucky), or some huge ones at a local electronics store.

so i was wondering, why are slider-pots so hard to find?

and even better, where can i find them (in non-industrial quantities)?

thanks,

matt

Paul Baker

how about here? http://www.mouser.com/?handler=data.listcategory&Ne=100&terms=potentiometer&Ntt=*potentiometer*&crc=true&Ns=SField&N=173

tangramkid

whoa thanks! exactly what i needed.

one other question. to use these sliders with a BS2, what should i look for in the specs? the rated voltage seems to usually be 150V or more, so that would work fine with the 5V or less that the BS2 puts out, right?

thanks a ton!

Paul Baker

yes 5V is fine, follow the diagram on page 352 (page 356 of the pdf) of the Basic Stamp user manual http://www.parallax.com/dl/docs/prod/stamps/BasicStampMan.pdf·and use the command·RCTIME to read the value.

<EDIT>·changed instructions of using POT to RCTIME since request was for use in a BS2 </EDIT>

Post Edited (Paul Baker) : 3/23/2005 9:05:47 PM GMT

Jonb

If you've ever used a mixer·for mixing music from multiple sources you'll notice the crossfader is a variation of the·slider pot. They are prone to accumulate dust and debris on the contacts resulting in "blind patches" and glitches. They need to be replaced often because the tracks are directly exposed through a "slit" and because they are used repetitively. I have noticed the addition of brushes on each side of this slit to catch dust and larger particles.·If you want a pot with lasting power then keep this in mind. The rotary pots are mostly better protected because of design. They are most often contained or mounted in such a way as to limit exposure.

Electronic Goldmine(go to 2nd page): http://www.goldmine-elec-products.com/products.asp?dept=1111


Have you seen the digital pots?

Post Edited (Jonb) : 3/23/2005 9:28:13 PM GMT

Paul Baker

A mechanical solution to the problem of debris is a slider who's wiper is bent 90 degrees, this causes the sliding mechanism to be mounted horizontally, out of the line of falling debris.

All proffesional boards use the sliders as input to a controller which then sets the gain of the amplifier, this overcomes the crackling that happens when moving the slider when feeding the audio signal through the slider itself. Also the controllers employ techniques similar to switch debouncing to make the audio transition smoothly even if the change presented by the slider is noisy or erratic. They also circumvent the blind patch problem by knowing that the current position cannot jump to a far different value without going through the values between.

MacGeek117

Also the're almost obsolete.
bugg

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Boe-bot: $229

Toddler: $249

Learning Google is your friend: priceless

tangramkid

ok the debris issue makes sense. thanks a lot, everyone.

to bugg: sliders are obsolete? can you explain? are there digital slider pots?

matt

EDIT: it's strange, i tried The Electronic Goldmine before, but i searched for "slider" instead fo "slide", so i got nothing. they seem to have incredible prices (a package of 2 or 4 for what you would pay for only 1 at mouser). so thanks a lot for pointing that out.

Post Edited (tangramkid) : 3/24/2005 1:05:35 AM GMT

MacGeek117

I believe they were the first pots to be produced.
bugg

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Boe-bot: $229

Toddler: $249

Learning Google is your friend: priceless

Robert Schwartz

That doesn't necessarily make them obsolete...

LoopyByteloose

Unlike audio uses [noparse][[/noparse]where you have to constantly see the sliders], a robotic use can mount them upside-down. That way the dirt falls out, not it. Vertical is another good, but second choice.

Also, it is quite possible to create a 'sealed' application. If you assemble them in a very clean, dust-less environment - you can extend the life. [noparse][[/noparse]make a box that is a mini-clean room and put only your hands inside?]

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
G. Herzog in Taiwan