potentiometer help

I decided to build a Spirograph for my girlfriend (i got her hooked on lasers!) but i would like to have more control over the speed of the motors. I was doing some research into different pots and came across "multi-turn" pots. I think theses are exactly what I'm looking for. The only issue I'm having is they are about $40 a piece!

Has anybody used multi-turn pots before? Do they work well? Should I keep digging around to find cheaper ones or is $40 about the norm?

Yes, I used them many times.

Yes, they work very well, for example, for fine adjustment.

And yes, you can find much cheaper than $40.

An example here, you can buy 2 pot (10 turn), of 1K Ohm and 2W for $2.75 each.

Thanks! So the resistance on these are 0 ohm - 1k ohm? because the first spiro i built i used 1k pots and there was hardly any control it was either on or off.

Theoretically yes, 0 Ohm to 1K Ohm, in 10 turn.

This was just one example, if for you aplication is not enough with 1K, this same seller has other values​​, such as this one, of 3.3K

Sweet thank you! I didnt even think to look on ebay for these.

It depends on the multiturn pot you're using too. Most are only adjustable with a screwdriver, but "volume-knob" pots will cost you more.

Another thing you might consider is just having two pots: one for coarse control, another for fine control. This can be as simple as using one pot with a wider range (coarse) and then put it in series with one with a smaller range (fine). Use the coarse-range pot to get close to the value you want, and then fine tune with your fine-range pot.

dfhrace said:

I decided to build a Spirograph for my girlfriend (i got her hooked on lasers!) but i would like to have more control over the speed of the motors. I was doing some research into different pots and came across "multi-turn" pots. I think theses are exactly what I'm looking for. The only issue I'm having is they are about $40 a piece!

Has anybody used multi-turn pots before? Do they work well? Should I keep digging around to find cheaper ones or is $40 about the norm?

Click to expand...

I usually use a screw based trimmer pot. 18 turns, <2 usd. If your into electronics/DIY, its always nice to have a stockpile of these around.
CT94EW102 Copal Electronics Inc | CT94EW102-ND | DigiKey
These generally allow for nice accuracy adjustments. However, you can have a 1000 turn pot and not necessarily get anywhere, mind posting the schematic in which they will be used?