wiring a potentiometer with a trimmer

[snk]

Hello,
I have a circuit where i woudl like to swap the resistor with a potentiometer + a trimmer (so i can set the range with the inner trimmer while the pot will allow to change the setting from the faceplate of the enclosure).
My question is : while i'm used to replace a resistor with a pot, i don't have much experience with the trimmer, and i'm lost with their pinning and wiring 
So, could anyone help me and tell me the right way to wire a trimmer before/after a pot, please ?

Would it be like this ?

What is the pinout on a trimmer ? The single pin on one side relates to which pin on a potentiometer ?

[Mark Hammer]

Like their much larger cousins -potentiometers - trimmers are usualy designed such that the wiper is the middle contact.  If you are using a trimmer to sub for some unpredictable resistance value, then you will be using it as a variable resistor.  In that case, only the middle and one of the other solder lugs are necessary to use.  Best practices recommends connecting the unused solder lug to the wiper.  This is done in case the wiper  - the weakest of the three contacts - fails to make good contact with the resistive strip.  At least you will still have the maximum value of the trimmer in place.

[mth5044]

Hello,

Doesn't matter which comes first, the pot or the trimmer, it'll be the sum of the resistance that matters in this situation. A trimmer is a small pot, and the PIN numbers will be the same. Do you have a link to the trimmer you're using? These, for example, show which pin is 3 and 1, and that would function the same as pin 3 and 1 of a pot.


https://www.taydaelectronics.com/200k-ohm-trimmer-potentiometer-cermet-1-turn-3362-3362p.html

When all else fails, use your multimeter to determine which is which.

[snk]

Thank you both for youre replies : it's perfectly clear 

Do you have a link to the trimmer you're using? These, for example, show which pin is 3 and 1, and that would function the same as pin 3 and 1 of a pot.

It is the same kind (but not the same value).
Oh ! I didn't even realize that the pins were already labelled on the blue box !

[PRR]

99% of the time, the "center" pin is the wiper, the others are ends.

Conventional pots put the three in a row E-W-E.

Some trimmers put the ends on one side and the wiper on the other.

And THEN you have the strange ones. There is a line of Stereo volume controls where the 7 connections are in one row and the order is not obvious. It actually makes sense if you bust one open and look what they did. Two carbon tracks on one wafer. To get the connections out without cross-overs, the terminals kinda have to be in odd order.

[snk]

Thank you, PRR.

[snk]

Hello,
This might seem dumb, but now I have the same issue with 3 wires  I can't figure out how i should wire a pot after (or before) the trimmer 
I am building a DOD 201 phasor.
There is a trimmer to bias the FETs. But i would like to try to add a small value knob to adjust the biasing a little around the sweet spot (set by the trimmer), so it may change the sound a bit.

Would this wiring work ?

(i fear it would be in parallel, like that ?)

[PRR]

> Would this wiring work ?

No. Like that, if you turn one knob one way and the trim the other way you have a short on Vref. While nothing will smoke, it's still not good. Also a 5k-10k pot there will overwhelm the 10k-22k feed to the Zener making Vref un-regulated.

Move one wire, add one resistor, use pretty-near values shown.

[snk]

Thank you, PRR.
So, a 100K pot and a 3.9M resistor, and i should be fine ?