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Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 5:17 pm
by unkle_psycho
So you used 50k for one driver and 10k for two? So if I want to try three should I try 10k? Or just go for individual adjustability... 6 50k pots

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 7:02 pm
by unkle_psycho
I just looked at potentiometers on digikey, they all seem to be 2w or less... and cost 8e or more WTF?

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 7:18 pm
by sdfoster22
From my understanding he used a 50k and a 10k on one driver, and they both worked separately. The charts he made I believe we're from resisters.

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 8:10 pm
by unkle_psycho
Do I need resistors? are the w designations on the potentiometers irrelevant, or do i need to find a 75w potentiometer?

I finally just pulled the trigger on 10 TRP drivers and a bunch of vesta strips. Two are for a friend who wanted to buy a 10w plant light from ikea for 50e. Two drivers and 8 1foot vesta strips were 50e at digikey, he will get quite a shock when he sees his plants bathing in 150w.

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 8:56 pm
by sdfoster22
The dimmer is only 10v max at 2mA. That's only like .02w or something.

I believe he used various resistors to determine how many ohms needed to dim the driver. A potentiometer dimms with resistance.

Although I don't know the difference between a and b pots. I know a is audio taper, and b is linear taper.

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 9:03 pm
by tazztone
i used a 50K pot, but upwards of 10K resulted in the driver already delivering it's max. 3A at 25V. so 10K is enough.
i will order 10K pots (and 20k as a security) from AliExpress and replace the A50K.
cost: 5pcs: 1.2$. plus some knobs.

A-type pots have a logarithmic curve (like the driver dimming response curve i posted)

on ali they only have cheap B (linear) pots.
my A50K is from digikey though. 0.7$ if i remember correctly

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 9:22 pm
by sdfoster22
tazztone wrote:
Wed May 02, 2018 9:03 pm
i used a 50K pot, but upwards of 10K resulted in the driver already delivering it's max. 3A at 25V. so 10K is enough.
i will order 10K pots (and 20k as a security) from AliExpress and replace the A50K.
cost: 5pcs: 1.2$. plus some knobs.

A-type pots have a logarithmic curve (like the driver dimming response curve i posted)

on ali they only have cheap B (linear) pots.
my A50K is from digikey though. 0.7$ if i remember correctly
Do you know what the difference between using an a pot vs b pot on these drivers would be?

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Wed May 02, 2018 9:26 pm
by tazztone
my imagination is too weak but i think A type would be better because its logarithmic curve would cancel out the logarithmic curve of the driver and result in a linear dimming experience.
however it doesn't make much of a difference if you use these mini displays i posted about earlier in this thread. you can set the dimming level according to their display.
i added a rocker switch to it so i can power it on only when i want readings.

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Fri May 04, 2018 12:51 am
by infosponge
How are you wiring them, in series? I'm still learning, ordered 8 TRP drivers and 12 vesta strips, automatically thought wire them in series because it's a CC driver but the output is 8-25 V, if I run 3 strips off one driver won't they only be pulling ~ 8 V each?

Re: cheap, dimmable drivers by "thomas research products" + display

Posted: Fri May 04, 2018 3:07 am
by sdfoster22
You have to wire these parallel so it splits amps between the strips. Which vestas did you order?