Power Supply Specs check plz

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kenreau

Power Supply Specs check plz
« on: 14 Jan 2020, 09:16 pm »



I’m uncertain of the replacement PS specifications I should look for.  I’m considering replacing a cyberpower ps that came from my ISP to power the Fiber optic to Ethernet conversion at my house service entry.

The PS label reads;
Input 100V-240V. 0.75 Amps
Output 12Vdc = 24W

I’m struggling with what Amp rating a PS would need.  Unless I have the wrong formula, wouldn’t a 2A PS be called for?  I’m not tracking with their 0.75A spec. 

I have an iFi 12Vdc (1.8A) wallwart PS I was thinking of trying out, but want to check if it’s output is in the ballpark first.

Thx
Kenreau


« Last Edit: 15 Jan 2020, 12:01 am by kenreau »

srb

Re: Power Supply Specs check plz
« Reply #1 on: 14 Jan 2020, 11:32 pm »
I’m struggling with what Amp rating a PS would need.  Unless I have the wrong formula, wouldn’t a 2A PS be called for?  I’m not tracking with their 0.75A spec.
According to your specs, the 0.75A is the max current required from the 100V-240V AC Input.

If the Output is 12VDC / 24W, then yes, a 2A supply would be in the ballpark, depending on the Power Factor of the circuit, which is why many power supplies have a VA rating as well as watts.

Also, it probably doesn't say 24VDC = 24W, what you're seeing as an equals sign is likely a long dash with three small dashes underneath it, an icon for DC.

Your 12VDC @ 1.8A replacement supply is in the ballpark, but of course it's always better to be on the high side than the low side as far as maximum current output.

kenreau

Re: Power Supply Specs check plz
« Reply #2 on: 15 Jan 2020, 12:03 am »
Thanks, Steve.  Correct on the == symbol for Vdc.  I just added a photo (I should have done originally)

Thx
Kenreau