Noob Question: Where is Lug 1, 2 and 3?

[fuzzymuff]

Where is lug 1, 2 and 3 in this pot symbol?

[Govmnt_Lacky]

You will come to realize that labeling of potentiometers is NOT standardized. If you go with the "common" method, lug 1 would be towards the CCW side of the diagram above. This would mean that Lug. 1 would be to the left. Then Lug 2 would be (and is always) on the wiper. Leaving Lug 3 on the right or CW rotation side.

Like I said, this is not always a standard on schematics. I don't know how many times I have built a circuit and wired pots to what I thought was the standard only to find that Lug 1 and Lug 3 needed to be reversed.

Hope this helps.

Also, when looking at a pot with the shaft facing you and the lugs down, they are numbered 1, 2, 3 from left to right.

[fuzzymuff]

You will come to realize that labeling of potentiometers is NOT standardized. If you go with the "common" method, lug 1 would be towards the CCW side of the diagram above. This would mean that Lug. 1 would be to the left. Then Lug 2 would be (and is always) on the wiper. Leaving Lug 3 on the right or CW rotation side.

Like I said, this is not always a standard on schematics. I don't know how many times I have built a circuit and wired pots to what I thought was the standard only to find that Lug 1 and Lug 3 needed to be reversed.

Hope this helps.

Also, when looking at a pot with the shaft facing you and the lugs down, they are numbered 1, 2, 3 from left to right.

Yes, that is what throws me off, specially if the lug #s are not noted on the schematics.    This is why I asked.  

What about if the pot symbol was shown as these?  Where would be lug 1, 2 and 3?  Note: the wiper arrow, lug 2 are on the oppsite sides, so where would be lug 1 and 3?

[LucifersTrip]

you can usually get it from the volume pot on the schematic since you know which lug is grounded....then you can only hope that the rest of the pots on the schematic are consistent with that

[deadastronaut]

lug 2 = arrow..

3 at top

1 at bottom...

usually...


or 3 left, 2 middle, 1 right......when 90 degrees cw

[armdnrdy]

This might explain a few things.

http://sound.westhost.com/pots.htm

[fuzzymuff]

Man...this can really be confusing..  Well, at least lug 2 is standardized to the middle lug

[Jdansti]

If you're breadboarding, just guess and if it's the wrong way, switch #1 and #3.

If you're building, solder the pot wires to the board, but use alligator clips to connect the wires to the pots (make a guess of the orientation). If it's wrong, switch the clips on lugs  #1 and #3 and try again. Once you get it figured out, you can make the permanent connections.

[fuzzymuff]

If you're breadboarding, just guess and if it's the wrong way, switch #1 and #3.

If you're building, solder the pot wires to the board, but use alligator clips to connect the wires to the pots (make a guess of the orientation). If it's wrong, switch the clips on lugs  #1 and #3 and try again. Once you get it figured out, you can make the permanent connections.

Thanks!!!  Great idea!  I knew that bag of alligator clips will one day come in handy.

[digi2t]

Yeah, like G_L said, annoying as hell that it's not standardized. Especially when you're building something like a Infinitphase, and find that 8 of your 9 control pots are wired backwards. 

[Govmnt_Lacky]

Yeah, like G_L said, annoying as hell that it's not standardized. Especially when you're building something like a Infinitphase, and find that 8 of your 9 control pots are wired backwards. 

God bless you Dino! 

[deadastronaut]

Yeah, like G_L said, annoying as hell that it's not standardized. Especially when you're building something like a Infinitphase, and find that 8 of your 9 control pots are wired backwards. 

at least it adds an element of surprise too...

[alparent]

I think 2 is always the center one!?
Sorry. I got back to my cave now.

[petemoore]

  "Resistive divider" is one way to think of it.
  1 resistor wafer divided by the wiper.
  But the wiper turns it into two variable resistors...by dividing/touching the wafer at either end or somewhere inbetween...depending on where it is set.
  Take a linear pot...should be linear...with the wiper dead in the middle it'll read about 50% / 50%...equalish resistance from wiper to either end. Can be wired 'reverse' [lugs 1 and 3] and the taper will be the same, but the knob turns 'backwards' [swap lugs 1 and 3 and CCW / Clockwise reverse also].
  There's an R-wafer in there, move the wiper and the linear pot'll say something like 60/40 or 35/65.
  The 'volume pot' [non linear taper], AKA better known as "Audio Taper"..has a 'wedged shaped wafer'...the resistance across this substrate/wafer gets thicker at one end [also lower resistance]. So...it won't read 50/50 in the middle, something more like 35/65 divide.
  They're all 'off' the total resistance [across the entire wafer] mark a bit, a 100k pot usually measures 87k or 93k or something like that...no matter, it still divides the same way...

[duck_arse]

on well behaved circuit diagrams, at the very least ccw is marked. sometimes a small arrow drawn perpendicular to the wiper is used to indicate increase - rotation and resistance.

[armdnrdy]

on well behaved circuit diagrams, at the very least ccw is marked. sometimes a small arrow drawn perpendicular to the wiper is used to indicate increase - rotation and resistance.

This symbol always confuses me! 

I know that it signifies a variable resistor...but I can never figure out which lug (1 or 3) to connect the wiper to!

[R.G.]

This symbol always confuses me! 
I know that it signifies a variable resistor...but I can never figure out which lug (1 or 3) to connect the wiper to!

There is a subtlety. A variable resistance is signified by a resistor with an arrow diagonally across the body of the resistor. A potentiometer is signified by a resistor body with an arrowhead pointing into the resistor body from the side, close to the middle of the length of the resistor body. This is a representation of the wiper lead, which may move toward either end of the resistor as the pot is adjusted.

The direction of electrical adjustment is commonly shown one of three different ways. First, there may be a small arrow *across the wiper lead* at right angles. This arrow points in the direction of "more", which is a clockwise turn of the shaft or an up movement of a linear pot knob.

I think of pot leads as "hot" "wiper" and "cold"; the distinction is that "hot" is the lead that the wiper touches when the control is fully "up". Cold is the fully "down" position no matter where that is on the actual mechanical pot body. This has served me well, as not all pots are adjusted from only one side. Some pots have dual shafts, or only a screwdriver slot in the center, and the idea of "clockwise" depends on which side you look at. "Hot" is always "more".

So with the arrow across the wiper symbol, the arrow points to "hot", wherever this is on the physical pot.

The hot lug is also shown by the letters "CW" on some schematics. And on some, there is only a dot on the hot lead in the schematic.

If there is neither an arrow, a dot, or "cw" or SOMETHING to denote the hot lead, the schematic drawer has figured that you're smart enough not to need that as a hint...   
... or lazy.   

[Thecomedian]

they should just use a system of in, out, ground. a clear demarcation like that mean's there can be no confusion in schematics.

[armdnrdy]

they should just use a system of in, out, ground. a clear demarcation like that mean's there can be no confusion in schematics.

Or just mark the potentiomer symbol with 1, 2, and 3 signifying lug 1, 2, and 3 of the physical potentiomer like we see in newer schematics and cad programs like Eagle.

[Thecomedian]

Well, I prefer the use of in - out - ground terms to cut down on the number dyslexia.