I need to find a fixed power supply to convert standard 110 AC to 18 Volt DC current.
It needs to have a low ripple (3 millivolt or less) so a switching supply will not work. I’ve been through all the catalogs and I can find everything but a fixed 18VDC power supply. If anyone knows were I can find one I would appriciate it!
Would it work for you to add extra filtering (eg: a couple capacitors) to an existing unit?
If you’ve got one that’s already reasonable, a thousand microfarads or so, with a parallel ceramic cap to snag the high-frequency junk might be all you need.
How much power do you need to supply?
Yea… how much current do you need to supply to the load?
How accurate must the load’s DC voltage regulation be?
Does it need to be fixed or variable?
Here’s a typical bench-top supply, with 0.5mV ripple: Extech 382202 (warning: PDF)
Did you mean a bench-top supply, or a module to go into a larger circuit?
Some 18 VDC, linear, open-frame power supplies here:
http://www.powervolt.com/bva.html#18volts
The ripple voltage is specified to be less than 3 mV p-p
An assortment of cheap, variable-output lab supplies can be found at these places:
Thanks to all who helped with my question. I only needed 250 mA max at 18vdc. I had a bunch of regulated 24vdc supplies, so I put a 7818 3pin voltage regulator on the 24V supply. Maybe not the best way to go. But it is a cheap solution that works. Again thanks for taking the time to help. Figure9…