Dumb Rectifier Question

[erpiii]

I'm in the process of building an F5 power supply and I have connected the secondaries from the toroid to the rectifiers and and got a low DC reading. My mains are at 122v AC, my secondaries are at 19.3v AC and the DC from the rectifiers (gbpc3506) is at 17.2v DC.

I guess my question is is this the right reading or is this a no load reading? Shouldn't it be about 1.4 times the AC voltage in? All the rectifiers read about the same 4(ea) for monoblocks.

One other question: The DC outputs from the rectifiers should be +to V+, - to ground from one rectifier and -to V- and + to ground on the other rectifier... Correct?

Thanks in advance.

[DF96]

We need a diagram.

[DigitalJunkie]

I'm assuming you do not have any filter caps connected yet? If so,that sounds about right. When you add the filter caps,the DC voltage should go up to the normal ~1.4 x AC.

[!]

Do you have capacitors after the rectifiers yet? If not, add one per power rail and take another voltage measurement, though I agree with DF96 that a schematic would be the most clear way to present the design used.

[erpiii]

No nothing connect yet, just the rectifiers.

About from the rectifiers to PS board, + to V+ board - to ground PS board / the other rectifier - to V- and + to ground on the PS board. Is that right?

[AudioSan]

yes, that i right.

[DF96]

I never guessed you would be measuring DC with no caps! Now it all makes sense. A full-wave rectified, but unsmoothed, supply has a mean DC value of 90% of the RMS AC input.

[AndrewT]

Before you damage you or your equipment, fit a bulb tester in the mains feed.
If the bulb lights up or glows more than very dimly, you have made a mistake.

Every time you modify or add to your wiring/equipment use the bulb tester to prove you have not wired in a fault.

[Pathogen]

here's a link that works the math and understanding of circuits, great for those in need.
Center-tap Full-wave Rectifier