Thanks for the replies people.
> And the 12V transformer would be it's RMS rating
> So you would have/need over 1`5.5V across C1
I think that's what confused me most. The diagram said 12V secondary on
transformer and 9.1+5 = 14V. Why didn't they just use a higher voltage
regulator instead of the zener + 5V? I promise no more questions about this
after this one.
Chuck H.
----- Original Message -----
From: "p.cousens"
To:
Sent: Sunday, August 17, 2003 10:06 AM
Subject: Re: [EE:] 24vdc from a 15vdc psu
> And the 12V transformer would be it's RMS rating
> So you would have/need over 1`5.5V across C1
>
> Peter Cousens
> cousens@biscit.biz
>
> > -----Original Message-----
> > From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On
> > Behalf Of Wouter van Ooijen
> > Sent: Sunday, August 17, 2003 2:28 PM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: [EE:] 24vdc from a 15vdc psu
> >
> > > If you can tolerate a novice question, I'll appreciate an
> > > explanation of how
> > > the output of the 7805 circuit in the
> > > http://www.mitedu.freeserve.co.uk/Circuits/Power/alarm_psu.htm
> > > diagram is 14v1. Thanks in advance if you will. If not, I
> understand.
> >
> > The output of the 7805 is 5 Volt, reffered to its ground pin. The
> Zener
> > keeps the ground of the 7805 9.1 Volt above ground (that is, if the
> > zener is operated at its nominal current), so the output of the 7805
> is
> > 14.1 Volt above ground.
> >
> > Wouter van Ooijen
> >
> > -- -------------------------------------------
> > Van Ooijen Technische Informatica: www.voti.nl
> > consultancy, development, PICmicro products
> >
> > --
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>
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