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Home > Archive > Electrical Engineering > July 2005 > Power supply for max 100mW from powerline (none isolated)
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Power supply for max 100mW from powerline (none isolated)
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| Cor Jansen 2005-07-07, 12:25 pm |
| Hello All,
I need to power a smal circuit (about 3 Volts, 30mA).
This circuit need to be powered from the powerline (220VAC).
The circuit need not to be isolated from the powerline.
I searched the internet for a simple solution for this, but could not
find it.
I hope there are special chips that do just this.
Does anybody has an idea?
Any help is welcome.
Thanks and greetings,
Cor Jansen.
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| gfretwell@aol.com 2005-07-07, 6:25 pm |
| On Thu, 07 Jul 2005 13:58:53 +0200, Cor Jansen <cor@dapdesignxdotxcom>
wrote:
quote:
>Hello All,
>
>I need to power a smal circuit (about 3 Volts, 30mA).
>This circuit need to be powered from the powerline (220VAC).
>The circuit need not to be isolated from the powerline.
>
>I searched the internet for a simple solution for this, but could not
>find it.
>I hope there are special chips that do just this.
>
>Does anybody has an idea?
>
>Any help is welcome.
>
>Thanks and greetings,
>
>Cor Jansen.
3vDC?
The simplest solution is a diode and capacitor in series with the line
in and another capacitor across the load. You can use a zener to limit
the voltage across the load.
I have used this for SSRs
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| Palindr☻me 2005-07-07, 6:25 pm |
| gfretwell@aol.com wrote:
quote:
> On Thu, 07 Jul 2005 13:58:53 +0200, Cor Jansen <cor@dapdesignxdotxcom>
> wrote:
>
>
>
>
> 3vDC?
> The simplest solution is a diode and capacitor in series with the line
> in and another capacitor across the load. You can use a zener to limit
> the voltage across the load.
> I have used this for SSRs
I agree but the OP might like to think about what a single
component failure outcome might be.
The clearance box at Radio Shack (or equivalent) can be a
good source of obsolete chargers going for pence - that is
where my "come-in handy" box full of small supplies came
from. One of these could possibly meet the requirement.
However:
Just for fun (?) I have cracked open a few of them and been
surprised to find that a number do have teensy SMPSU boards.
Some implement a complex charging profile which often isn't
what is required. I suppose that they could be modded but my
eyesight isn't up to that any more. The standard mains
transformer type is a better bet for this application..
--
Sue
--
Sue
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| Jeff Thon 2005-07-07, 11:25 pm |
| Look at this. It may be useful.
http://www.selectronic.fr/includes_...xim/MAX_611.pdf
"Cor Jansen" <cor@dapdesignxdotxcom> wrote in message
news:42cd18fa$0$91328$e4fe514c@news.xs4all.nl...
quote:
> Hello All,
>
> I need to power a smal circuit (about 3 Volts, 30mA).
> This circuit need to be powered from the powerline (220VAC).
> The circuit need not to be isolated from the powerline.
>
> I searched the internet for a simple solution for this, but could not
> find it.
> I hope there are special chips that do just this.
>
> Does anybody has an idea?
>
> Any help is welcome.
>
> Thanks and greetings,
>
> Cor Jansen.
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