Very small, very long life, 10 turn trimmer pot?

Bourns 3590S-1-502 trimpot is 5K Round - 0.875" Dia x 0.732" H (22.23mm x 18.60mm). Bourns 39LA-1PB-103 trimpot is 10K Round - 0.512" Dia x 0.217" H (13.00mm x 7.01mm) which is smallest thru-hole one turn pot. Panasonic EVW-AE4001B14 trimpot is 10K Square - 0.606" L x 0.417" W x

0.087" H (15.40mm x 10.60mm x 2.20mm) which is smallest surface mount one turn pot. Above found online via DigiKey; did not try harder. Did not try to find the Bourns Knobpot which includes multi-turn capabilities; the knob is the largest part as everything but mounting is inside.

Trimpots have really really short mechanical lifetimes. You might want to think about a conductive plastic pot, as used in audio.

Cheers,

Phil Hobbs

Trimpots have really really short mechanical lifetimes. You might want to think about a conductive plastic pot, as used in audio.

Cheers,

Phil Hobbsn

An encoder would have a virtual infinite lifetime The sensor for the encoder would be fully serviceable. Much more precise capability.

yes. i realized that trimpots are not the right thing to ask for but i guess i asked simply because they can be very small. i thought to give them a whirl since i gave up on encoders...i have found an encoder from bourns, the 3375, but it is obsolete.

which would work for what i'm looking for. is there any other models out there just like this in terms of dimensions?? tocos makes a 7mm one, that is too large.

i'm not looking to use some part dealer service where they require you to have a few hundred dollar minimum order. something that is readily bought.

On Jun 20, 5:20=A0pm, Generalspecific wrote: \\> > >> that will be used for a knob that will be used a lot.

There's an outside-the-box possibility in trim capacitors. Little glass tube trimcaps (just solder a shaft onto the plunger) are available about the right size. There's just the small problem of detecting the few-picofarads value change.

Old auto radios used a sliding slug in a coil for some variable inductors; one can tune with a brass screw poking into the bore of a small solenoid inductor.

In either case, you'll have to look for small phase shifts, or measure an oscillator frequency.

ight want

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_obsolete.pdf

Is this obsolete just because of RoHS? If so, there may be a lead-free replacement (with a different part#).

Also, this datasheet shows a continuous mechanical angle. Is that what you want? There are also digital pots out there (Maxim?). But they're expensive.

obsolete.http://www.bourns.com/pdfs/3375_obsolete.pdf

Trimpots and pots in general are becoming obsolete.

Maybe you should try a 21st century solution?

JAM

If they are, it's happening pretty slowly: If you're doing mass manufacturing where labor is cheap, trimmers are often still over any electronic equivalent -- especially if you can't figure out a way to freely measure whatever it is you're trimming. (E.g., if you're producing 10,000 of something a day, having a $10,000 spectrum analyzer around is cheap if you can use it to trim each widget -- far better than adding $1 to the manufacturing cost of each widget.)

Although as Joerg likes to point out, with some savvy engineering often you can get rid of all type of adjustments completely and he's never used them... although I kinda wonder how many of them would have needed trim pots/caps if laser trimming weren't available. :-)