I have a Farnell G24-5S PSU which I'm installing in an insulated enclosure so it can be used for powering the multitude of battery operated toys that my 6-year-old son has. The binding posts will be removed and fitted on the top of the enclosure together with a combined 7-seg LED volt / amp meter so the output can be easily adjusted and monitored.
In the attachment you can see that a 25K pot across two front-panel terminals will enable the output to be controlled from approx. 1 ~ 25V. I already have a 1W 25K Linear pot connected and it does adjust the output as intended. But it's only a 270deg pot and it's a real struggle getting to the actual voltage I'm after for a particular toy.
A 3- or 5-turn pot would make adjustment so much easier and more accurate but I'm having no luck finding one at 25K. So I've been looking at coarse / fine adjustment using 2 pots in series (there are more values available that add up to ~25K) but after researching what I initially thought would be a pretty simple solution I am now stumped; there are quite a few different methods that may or may not be suitable for my project and I'm unsure which way to go. Also I can't ascertain what would be an ideal ratio between the two pots i.e. 22K + 3.3/2.7K, or 20K + 5K1...
Has anyone already accomplished what I'm trying to do, or have any pertinent suggestions?
In the attachment you can see that a 25K pot across two front-panel terminals will enable the output to be controlled from approx. 1 ~ 25V. I already have a 1W 25K Linear pot connected and it does adjust the output as intended. But it's only a 270deg pot and it's a real struggle getting to the actual voltage I'm after for a particular toy.
A 3- or 5-turn pot would make adjustment so much easier and more accurate but I'm having no luck finding one at 25K. So I've been looking at coarse / fine adjustment using 2 pots in series (there are more values available that add up to ~25K) but after researching what I initially thought would be a pretty simple solution I am now stumped; there are quite a few different methods that may or may not be suitable for my project and I'm unsure which way to go. Also I can't ascertain what would be an ideal ratio between the two pots i.e. 22K + 3.3/2.7K, or 20K + 5K1...
Has anyone already accomplished what I'm trying to do, or have any pertinent suggestions?
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