Trimpot / turnpot brands? - Page 1
Forum section: electronics / projects

author: ftransform
author_rank: Frequent Contributor
timestamp: October 18, 2012, 11:20:43 am
content: So you can find 100 20 turn trimpots on ebay for 30$ from hong kong, or buy then from vishay/etc at 2$ a trimpot...What can be expected of 1())====Dlow brand trimpots? The wire wound ones from bourn are very expensive (15$ EACH).. so I am more interested in the cermet ones.How many times can you adjust these cheapie trimpots along the range before they break? Do they offer smooth operation (at first)?I figure i'd rather buy 6 trimpots for the price of one, and just throw em out after I adjust them a few times rather then spend money on the more expensive ones... Will it matter at all once they are glued down with loctite?suggestions?

author: Rerouter
author_rank: Super Contributor
timestamp: October 18, 2012, 11:57:56 am
content: the thing with trimpots and this comes very much into the picture depending on what your doing with them is the temp coefficient (working calibration), if oxidisation or gunk from a non sealed type matters (multiple calibrations over time) and how long you expect your product to last,from the sound of things they are only for initial calibration, in which case only temp coefficient should matter to you, as where the wipers contact as long as it doesnt move should not be effected by oxide to any large effect, as for locktight, i personally prefer to use generic red nail polish (yes i am a man), as it holds them firm for over a decade, and cracks easily enough under torque from a screw driver for later calibrations or repairs,

author: ftransform
author_rank: Frequent Contributor
timestamp: October 18, 2012, 12:14:15 pm
content: oooo so now i have an excuse for those cosmetics...is the adjust-ability of a x turn trimpot the same across the board? I've read complaints on some forum that the cheapie 10 turn ones offered less adjustibility then a good brand single turn one... hard to imagine for me really..

author: Rerouter
author_rank: Super Contributor
timestamp: October 19, 2012, 01:18:37 am
content: that has to do with static wiper friction, something you generally have to pay to get rid of,basically on the cheap ones where the tolerances are more relaxed you will need to apply a bit more force to get the wiper moving, the issue with this is, when you are very close to where you need to be is you will tend to overshoot past the mark and unless you go away from it and come back you likely wont reach it,as for a cheap 10 turn lacking to a 1 turn pricy, that is a little bit of a stretch,

author: Smokey
author_rank: Super Contributor
timestamp: October 19, 2012, 02:19:05 am
content: Trimpots are near the top of the list of components I wouldn't skimp on. If you are using them on a one off personal project or something, fine, go for the Chinese ones. If it's anything you are going to sell, or in a critical circuit get brand name.Especially if you rely on them being accurate and repeatable, any mechanical component that people might have to interact with should be robust. At best it will fail and the product will just stop working. At worst it will put a crazy bias on some circuit and things will blow up. As far as cycles before they break, that's the thing with low quality control Chinese parts. You never know. Could be 1, could be 100. I've heard of cheap trimpots starting to be non-linear, have gaps and skip around, and fail both open and closed.Bourns is a good quality company. Their support is top notch as well and their prices are pretty good.As far as gunking trimpots, you don't want anything thin that will run down into the pot if it's not sealed. They make stuff just for this. Comes in little squeeze tubes. I'll have to look it up when I get back to work tomorrow.

author: w2aew
author_rank: Super Contributor
timestamp: October 19, 2012, 05:29:41 pm
content: And one final point to remember - trimpots are NOT a substitute for a control-type potentiometer. A control-type pot is typically rated for many, many thousands of "wipes" while trimpots are rated and designed for much less. I've seen trimpots that are rated for only 10 or 100 wipes. Thus, the normal diddling back an forth to adjust or trim a circuit will use up a goodly portion of their rotational life. Do not use a trimpot on an adjustment that is going to require many multiple adjustments unless it is specifically rated for the number of "wipes" you'll need.

author: robrenz
author_rank: Super Contributor
timestamp: October 19, 2012, 05:42:32 pm
content: Are we talking about pots or toilet paper?

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 19, 2012, 06:26:45 pm
content: Quote from: robrenz on October 19, 2012, 05:42:32 pmNot sure what you do with toilet paper but the "10-100 wipes" was a giveaway for me...