Picking the right Potentiometer?

Philip-O

Well-Known Member
I´ll keep it in mind. These have an indicator showing their current position, but you are right in pointing out that 10 turns is way too "precise".



You are welcome.
But I would not like a 10 turn pot because as it says it needs to be turned 10 times for tall the way up and down and you can not make a scale to easy see how it´s set.
I just bought these:

Rilla.
 

Philip-O

Well-Known Member
Kono, although I´m a noob from what I´ve gathered in the forums it has to do with two things: 1. Cheap pots are usually not really 100k but 97k, 95k or the like. So by adding the resistor you ensure that you have at least 100k resistance and thus 100% power (not as if you have the system dimmed to 97%, 95%, etc). 2. Drivers should not be dimmed under 10% (look into the spec sheet for your driver), so by adding the 10k resistor you ensure that you cannot dim below that percentage.

If you are using a single pot to dim 2 drivers you should use a 50k pot and a 5k resistor (the formula is 100k divided by the number of drivers). If you used a 10k resistor with a 50k pot it would still work, but you would not be able to dim below 20%, as there would be a 10k resistance.

For what are resistors? To dim 10-100%?
What if I wire only 100k potentiometer to driver?
 

nevergoodenuf

Well-Known Member
What he^ said. If you are building multiple lights, the $2 dimmers at Fry's or where ever you get it will be very inconsistent. Wattages will be all over the dial. If this doesn't bother you, then just use a watt meter to mark your wattage. If you can't stand the cheap, inconsistent and prone to failure dimmers, then look at the $9-$20 dimmers. You can see the quality difference and also feel it. Every dimmer has been evenly spaced and almost identical to the other.
 
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