Reducing high voltage.

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Cougar
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Reducing high voltage.

Postby Cougar » Sat Jan 18, 2014 8:14 pm

I'm looking for the easiest and smallest way to reduce high voltages (16.8v-25v) to 3v. And similar, off the same circuit a 12v source.
The 3v is for a larson scanner to sit in the front, and the 12v will be for some kinda headlights in the near future.
I run 4s LiPo at the moment, but will be bumping up to 5s and 6s by the summer.


I'm attempting to make some LEDs for my RC car. I've overcome one problem but now stuck at this point. I've made a 3rd channel switch to turn the source on and off, but now I need to reduce the voltages...

Help pleasseee. :)
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phenoptix
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Re: Reducing high voltage.

Postby phenoptix » Sat Jan 18, 2014 8:28 pm

Voltage regulators like the lm317 http://www.phenoptix.com/products/555-t ... nt-timer-2 (need to change that URL!) Would most likely do the trick

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Re: Reducing high voltage.

Postby phenoptix » Sat Jan 18, 2014 8:43 pm

Image
Image

3.03V R1 = 330, R2 = 470

11.83V R1 = 390, R2 = 3300
12.40V R1 = 370, R2 = 3300


From Reuk which is a pretty good resource. Should be able to get the voltages you need with with some fairly common resistor values!

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Re: Reducing high voltage.

Postby Cougar » Sun Jan 19, 2014 1:01 am

I will be completely honest... No matter how much I've tried to understand resistor values and circuit diagrams over the last few years I can't grasp it at all, really struggling to make sense of it.
That small diagram is kinda confusing, and I know it is basic.

Though, some of it just made sense, which is epic this time of night.
Might be a good idea to pick a book up or something and learn from the start. :mrgreen:

So this would be the outcome, assuming I want the 3v.

Image

Thanks for the research for me, just looking at what you have done has made some sense, if I got that right.

Steve
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phenoptix
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Re: Reducing high voltage.

Postby phenoptix » Sun Jan 19, 2014 7:14 am

I'll get a breadboard on Monday and send a PIC of it all hooked up. Vout on your diagram should be 3.03v and the bottom line ground (-ve)

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Re: Reducing high voltage.

Postby Cougar » Sun Jan 19, 2014 11:58 am

Ah, I can see my error. Makes more sense now. :roll:

Thanks for doing that, I really appreciate it.
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Re: Reducing high voltage.

Postby phenoptix » Sun Jan 19, 2014 4:59 pm

No worries, I really appreciate the question! Has made me think that we stock all of the items you need and they should be available in an easy kit. LM317, two resistors, capacitors, a bit of strip board and probably even a 2.1mm barrel jack for those using a wall wart or similar.

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Re: Reducing high voltage.

Postby Cougar » Sun Jan 19, 2014 9:15 pm

Excellent. Once all sorted you have a customer for a few kits, minus the jack, as I have batteries. :mrgreen:

Also, what would you brightest white LEDs/SMDs be? Depending on size, Each headlight doesn't want to be over 25mm diameter, with casing
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Re: Reducing high voltage.

Postby phenoptix » Sun Jan 19, 2014 9:29 pm

1206 and plcc2 pack some punch

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Re: Reducing high voltage.

Postby Cougar » Sun Jan 19, 2014 10:38 pm

PLcc2 look good. Any due date on stock? :)
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