[aprssig] Looking for a power supply

Dave Baxter dave at emv.co.uk
Fri Aug 18 03:47:30 CDT 2006


Universal input with 24VAC output could be a tad expensive, and
problematical to do safely (for the device powered by the 24VAC that

SMPS's exist that'll do 48V and 12VDC, and with universal inputs, but if
you also want a LF 24VAC (50 or 60Hz) you'll need something special.

Can the camera actualy use DC, or does it realy "Need" AC?  (Pan/Tilt
drives etc?) I only ask, as its use of AC may be for legacy
compatability otherwise.  It'll be DC internaly anycase...

Could it use square wave AC?  At least you could use a 24V DC supply and
a crude LF H-Bridge driver to produce that or a modified sine output
from 33.9VDC, much as many of the cheap car to mains inverters do...
(HF converter to 155V (or 310V) then H-Bridge to 50 or 60Hz Mod Sine

Or look for another camera system that uses DC drives for pan tilt focus
and zoom etc, If that's the problem.  They are about...

Another thought, go to powerstream.com  Maybe they can help?
http://powerstream.com/  Unless you've already been there...

Just thoughts....

Dave G0WBX.

> -----Original Message-----
> From: Mark Fellhauer [mailto:sparkfel at qwest.net] 
> Sent: Thursday, August 17, 2006 4:45 AM
> To: aprssig at lists.tapr.org
> Subject: [aprssig] Looking for a power supply
> Okay, I'm tired of searching through catalogs and online 
> vendors, for something that may not exist...  Maybe someone 
> on the SIG can help.
> I need a power supply for an embedded aprs-like device, that 
> gives me 12 VDC, 48 VDC, and hopefully 24 VAC.
> It has to be small, can be open frame even.  Would prefer it 
> takes universal AC 100-240 VAC as an input, but 110 VAC only 
> would be fine.
> I need about 5 amps for 12 volts, 1 amp for 48 VDC and 1 amp 
> for the 24 VAC outputs.
> 12 volts is for a motherboard, 48 volts is for 
> power-over-ethernet, and 24 
> VAC is for a video camera.   The unit has to be relatively 
> small, ideally 
> 3" x 6" x 2" or less.  And it has to be UL/CE and RoHS compliant.
> Right now I'm doing this with two power bricks and a doorbell 
> transformer, and it's so embarassing...
> And hopefully the solution would be relatively inexpensive, 
> less than $100 in lots of 10.
> Regards,
> Mark

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