Arfa, are you sure about that? I thought you were supposed to divide by the square root of 2, not multiply by it. Oddly, my friend says there is no smoothing cap in the circuit. I did not ask him whether he checked voltages again, but I will.
Arfa is spot on ! 24v as near as makes no difference.
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Best Regards:
Baron.
Hi Smitty Peak DC out is root 2 (1.414) *times* the RMS AC in, so with a resevoir cap of sufficient size, and not too much loading and source impedance, that's about the level of DC that you would measure on a normal multimeter. You are thinking of calculating the AC RMS figure from the DC where you
*divide* the DC level by root 2 (or multiply by 0.707).The fact that there is no resevoir cap, throws a bit of a spanner in the works when it comes to measuring the 'DC' out from the bridge because, whilst by strict definition it *is* DC, what you will actually have is a train of unipolar pulses, which the meter will make some attempt to integrate into a DC level that it can display. Obviously, this will be a misleading figure, and may even differ between an analogue, and a digital meter. The meter reading of "12" might well have been 'correct' in this case - if you see what I mean !
I wonder what additional circuitry this supply is powering ? It can't be anything 'electronic', as such a raggedy-arsed rail would play havoc ...
Arfa
:> > >
Now that it is fixed measure at the same points again and see what voltages you get. That should give an indication as to whether the original readings were as they should have been.
multimeter.
probably just for a solenoid for PTO activation off the motor , for slide carriage/carousel movement.
Thanks Arfa, and others. School was over many years ago, and never having made the subject into an occupation, as I had planned, the theory quietly slipped away ...
Friend obliged my request for another reading, and now shows 28 VDC out of the unfiltered bridge, with his Fluke handheld meter. Would have saved us all a lot of bother if I'd recognized that 12 VDC as faulty right off, rather than thinking it was spot on.
N. Cook is correct, the DC only drives a relay to operate the carousel on command.
Smitty
Ah yes ... ! Hindsight is a wonderful thing ! Still, at least if it ever goes wrong again in any of our lifetimes, we'll have a better idea where to start looking ! You say about theory quietly slipping away. Sometimes I despair at the things I've forgotton - often from just 5 seconds ago - but then marvel at other 'useless' information and facts that seem to have stayed with me taking up space for ever. And even with all the stuff I've forgotten, and the very 'normal' upbringing and education I had, allbeit at a decent school, my three grown children think that I am a 'genius', just because I know something like the fact that New York is north of the equator ...
Makes you wonder just where we're headed over the next couple of generations, and whether the current world crisis is anything to do with the general standards of education and morals that our current and previous generations enjoy ... :-\\
Arfa
A few years ago, on "Who Wants to Be a Millionaire," some fellow made it to the million dollar question. Now, once they get above 25,000, I'm hopelessly lost most of the time.
So I was absolutely shocked when they trotted out a factoid that I've known in my sleep since I was seven: the distance from the earth to the sun. "Doesn't every single person in the entire world know that?" I ask aloud incredulously. And now it's a *million dollar* (multiple-choice no less) question. Unbelievable.
We know what we know.
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