Trimpots.. how in god's name are they read!

[RollingElbow]

Ok, so past hour has been spent looking at the schematic and layout ( i never trust the layout alone) and i understand regula pots but on trimpots how do you know which is 3-2-1?! I can't tell what is front and what is back on this thing so for the love of god someone help me out with a link that might explain it. Yes there is an arrow on it that points up and the middle leg sticks out from the other two. That's the best i can do. thanks.

[birt]

2 is the middle lug/wiper. the others don't really matter because you set them once and just leave em. so it's not really a problem if they are wired backwards.

[Johnny Guitar]

Well, with a trim pot, as long as you can tell which is the wiper (the middle leg as you call it  ) it really doesn't matter which of the other two legs is which. You turn the trim pot one way, if it sends the circuit in the wrong direction, just turn it the other way.

We have a tendency to want to turn front panel knobs clockwise to get MORE of that effect. When FP knobs are backwards, it is counterintuitive to use that control.

[mongo]

I've seen trimpots on commercial stuff (radios,hi fi amps etc...) marked with numbers like 103,103,225, how do you read those???


Thanks!

Andy

[RollingElbow]

Interesting... so essentially when you are done, if you experience problems you might have to go through all your trimpots and turn them in the other direction if nothing works!   So to simplify, I guess you put them all in the same direction (wipers facing west for example) so that you know you have to turn all of them back in the same direction if you experienceproblems.

It almost defies logic! Yet it is what makes this interesting i suppose.. thanks.

[Johnny Guitar]

Often a trimpot is merely a tweak or fine tuning of an effect, and frequently done with a meter while monitoring some voltage somewhere.

I've seen trimpots on commercial stuff (radios,hi fi amps etc...) marked with numbers like 103,103,225, how do you read those???

Just a guess but I imagine the first two digits are the first two significant digits of the pot value, while the third digit is how many mutliples of 10 to multiply it by (kind of like scientific notation). So for the two examples you gave I'd guess the folowing:

103 = 10 X (10 X 10 X 10) = 10K

225 = 22 X (10 x 10 X 10 X 10 X 10) = 2.2M

But I always put a meter across the outer lugs of a pot if I'm at all unsure what value it is.

[Noplasticrobots]

It all depend son where West is...

[amz-fx]

i understand regula pots but on trimpots how do you know which is 3-2-1?! I can't tell what is front and what is back on this thing so for the love of god someone help me out with a link that might explain it.

It almost never matters. Don't worry about it.   Make sure the middle leg goes to the right place and then the other two can go either way.

-Jack

[zachary vex]

I've seen trimpots on commercial stuff (radios,hi fi amps etc...) marked with numbers like 103,103,225, how do you read those???

an easy way to read these is to imagine the first two digits followed by the third digit's number of zeros... like 103 is 10 followed by 3 zeros, or 10,000.  225 would be 22 followed by 5 zeros, or 2,200,000 ohms.  this type of marking is common on capacitors too, and in that case it's almost always referring to pF.  a 10 pF cap is marked 100, and a 100 pF cap is marked 101 using this convention! 

[mongo]

Thanks!! I've learned something today!

A+

[RollingElbow]

We've all learned something today! This will help someone else out as well down the line..(provided they use the search function) . Now to do something about my compass 

[markm]

There's a search function here......