1. Home
  2. Electronics Repair
  3. Log/lin pot A/B suffixes & prefixes

Log/lin pot A/B suffixes & prefixes

Does anyone know of any standard or authorative source for such designations. eg

50KA - lin ? 50KB- log ? 50KAB - lin/log , semilog? 50KBA - log/lin ? and does a B prefix mean a centre pick off fourth terminal, or 1/3&2/3, or any fixed track tap terminal or what if anything a B prefix means. ? And while at it any other letter designations eg for cosine track, or even wire/wound etc

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to
N Cook
Loading thread data ...

I think it`s A = lin, B = log except when it isn`t ;)

the marking conventions changed some time ago

law of a pot should cause no grief to anyone, right? Wrong! It wouldn't have been so bad if someone hadn't decided to change it, and even then, it wouldn't have been so bad if there was no overlap between the "old" and "new" "standards" ... I think you can see where this is headed by now.

make assumptions, or you can easily get the wrong type - especially if working on older equipment.

marked as 100K - but not always. The coding system used for capacitors is sometimes used as well (especially on small trimpots), so a 100k pot could also be marked as 104 - 10, followed by 4 zeros, or 100000 (100k) ohms.

formatting link

Ron(UK)

Reply to
Ron(UK)

Are you the author? If so, congratulations for a useful little piece.

--

*Some people are alive only because it's illegal to kill them *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW To e-mail, change noise into sound.

Reply to
Dave Plowman (News)

No no, it`s part of a wonderful resources site ESP which contains a huge amount of useful info

formatting link

I thought that I`d put a attribution to the site just before my header, but it seems to have gone awol.

Ron(UK)

Reply to
Ron(UK)

A = linear (European) or Audio taper (Japanese).

B = 'log' taper (European) or linear (Japanese)

Graham

Reply to
Eeyore

There are no meaningful conventions except that C universally means 'reverse log'.

Graham

Reply to
Eeyore

so its a matter of ignoring everything other than the likes of 50K and measuring ohms at 1/4,1/2,3/4 and full track

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to
N Cook

connecting the pot to an analogue meter and sweeping from end to end will show whether it`s log or lin.

Ron(UK)

Reply to
Ron(UK)

What does the resistance value have to do with it ?

1/2 rotation only. Most of the tapers you're likely to find in audio are typically specified @ 50% rotation as a percentage of 100% resistance. Audio and reverse log are usually 15% for example (depending which end you're measuring from) although I have used semi-specials such as 5% reverse log for mic amp gain pots.

Graham

Reply to
Eeyore

You don't even need to go that far. Set to approx 1/2 travel and measure one side. Linear will be near 50% - log very much not.

--
*I feel like I'm diagonally parked in a parallel universe*

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.
Reply to
Dave Plowman (News)

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.