Quick Eagle question: German abbreviation for trimpot pad labels

Thanks. Knowing the German abbreviations would be a help.

Cheers

Phil Hobbs

Don't trust ANYTHING in a library! You never can be sure the person who created the library had the same part in mind.

Jon

I seem to always get at least one pot in backwards or a switch the wrong way in every first run of a pcb. Can't you measure the pot and see?

George H.

Here's my wild guess at these abbreviations:

A: Anfang (start) E: Ende (end) S: Schleifkontakt (wiper)

Unfortunately that still does not give any info, which way is supposed to be start and which way is end.

Usually "start" is considered the position at which the pot is supposed to provide a signal representing a "minimum quantity", usually that's CCW on rotating pots, down or left on sliders, whereas "end" is supposed to represent a "maximum quantity", typically CW rotation, up or right sliding motion.

Note that this is all assuming the library guy used some established practices and common sense (a semi-rarity here) and the Germans also have a saying like "trust is good, verification is better".

Regards Dimitrij

I can when the parts come in. Trouble is, the board needs to be ordered by then. It isn't the absolute end of the world if it's backwards, because there's only one of them. I'd just like to know the German abbreviations, e.g. in optics, s polarization is when the E field vector is normal to the plane of incidence. S is short for "senkrecht", i.e. perpendicular.

I assume A and E are something similar, but I don't know what. I suppose E could be "entgegen", i.e. "against" or "contrary".

Cheers

Phil Hobbs

Could well be, thanks.

Cheers

Phil Hobbs

Am 02.05.2014 21:55, schrieb Phil Hobbs:

A could stand for Anfang, or beginning E could stand for Ende, you guess it S would be "Schleifer" or wiper.

Not that I ever have seen that, and at least A and E would not be very helpful.

Cheers, Gerhard

Our schematic symbol for a pot has a dot on one lead, the CW end. But yeah, it's easy to get switches and pots, or the corresponding PCB silkscreens, wrong.

Different trimpots have different internal construction. Some work the "obvious" way but most have internal crossovers to make the mechanics work better. The crossovers trash the high frequency behavior.

This is a really, really tiny pot with no crossover. It works up to a GHz or so.

Nice. What is it?

Cheers

Phil Hobbs

It's a Murata 2 mm thing.

Cheap, about 17 cents or something. You need a special ceramic screwdriver to set it, it's so small. The adjustment is hot.

"Phil Hobbs" schreef in bericht news:E6GdnTKv9pcAbf7OnZ2dnUVZ snipped-for-privacy@supernews.com...

Hi, all, and especially Joerg,

My beautiful layout hunchback is laying out the boxcar lock-in board. It contains a current source to drive the LED, which has a trim pot.

Normally over here, they're marked "CW" and "CCW" so you know which end is which.

In the Eagle library, the ends are marked "A" and "E", and the wiper is "S".

Anybody know which of the ends is CCW?

Thanks

Phil Hobbs

-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics

hobbs at electrooptical dot net

I have a schematic in which potentiometers are used with this symbol. They are volume controls in an audio circuit and the "A" is connected to GND. See partial schematic below. The original was made using Eagle.

------+------+------ | | | | .-. | | | | | | | ---+ '-' | | | | |E | | .-. S || | |/ | | '-' | | |A | +----- | | | | .-. .-. | | | | | | | | | | | '-' '-' | | | | | |

------------------+----+-------

petrus bitbyter

It's already that way, because the three leads are in a row. (I like through-hole for RA pots and some connectors.) Reversing the pot is no big deal in this application, but since (a) a 10-minute web search turned up zilch, and (b) there are a number of intelligent German-speakers who post here regularly, it was natural to ask.

Cheers

Phil Hobbs

Not directly related, but an interesting sidelight, and possibly very useful. Both John and I do a lot of odd, high speed stuff, and I value his advice very highly.

Cheers

Phil Hobbs

Me? I don't own a trimpot factory.

The crossover thing is relevant, because it means you can't usually say, just by looking, which pin on the trimpot is the CW or CCW end.

Bust open some pots and see what I mean.

From german teq I used to use & repair:

Eingang = Input

Ausgang = Output