[sdiy] Quick and Easy Power Question

[Oren Leavitt]

Hi Shawn,

You'll be perfectly fine with the two PSUs sharing the 24VCT 
transformer, as long as both PSUs share the same GND.

For the input filter caps, personally I'd go with 4700µF or more to be 
safe on ripple.

- Oren

On 11/1/20 7:03 PM, Shawn Rakestraw wrote:
> Here is the circuit for the PSU. You guys / gals helped me iron this 
> one out almost a year ago. This schematic is for 1 amp on the +12 and 
> -12, but I have built a couple now with 2 amps on the +12 and it does 
> not get too hot for the regulator. The transformer would be your 
> standard cube shaped iron core center tap transformer (120V to 24V). 
> Circuit is based on Electronotes.
>
> My main concern was that I want to have 2 of these psu boards off a 
> single transformer. I suppose I could also have a transformer for each 
> psu board and just split the mains before the transformers too.
>
> As long as I am posting the circuit, I will ask one more question. 
> This one, much more generalized. My filter caps are only 1000 uF and 
> the circuit seems to work perfectly fine. I see others using an 
> outrageous number of caps in parallel with much higher values. Is this 
> advantageous or is it pure overkill and bordering on being a problem 
> due to not fully charging the caps?
>
> psu.png
>
> On Sun, Nov 1, 2020 at 7:16 PM Ben Stuyts <ben at stuyts.nl 
> <mailto:ben at stuyts.nl>> wrote:
>
>
>     > On 2 Nov 2020, at 00:49, Shawn Rakestraw
>     <shawnrakestraw at gmail.com <mailto:shawnrakestraw at gmail.com>> wrote:
>     >
>     > If I use a transformer that is say 24V and 6 amps, can I connect
>     2 of my power supply boards to that transformer? There's nothing
>     wrong with that, right?
>
>     Hard to say without any additional info. It really depends on the
>     topology of the power supply. For example, if you have a single
>     wave rectifier on the input of the psu, and you have connected
>     both psu’s in reverse, you will probably short-circuit your
>     transformer.
>
>     Ben
>
>
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