Maker Pro
Maker Pro

DC power supply from AC through bridge rectifier

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
I make it something like [REMOVED ANSWER]

Or something like that. It's a fairly meaningless figure because any additional load or other fluctuations will change it
 
Last edited:

gorgon

Jun 6, 2011
603
Joined
Jun 6, 2011
Messages
603
Normally the mains voltage will fluctuate a bit over the day/load, I would guess as much as +/-10%. Distance from the nearest distribution transformer will also count.
To get a stable 6V output from the power you'll need a regulator after the rectifier/capacitor bank. Most linear regulators need a bit of overhead voltage to perform, meaning that the base AC voltage from the transformer need to be a bit higher than the required output voltage.

The circuit you post will give around 7V unloaded or with a small load. Loading it will reduce the output as Steve said.

TOK ;)
 

poor mystic

Apr 8, 2011
1,074
Joined
Apr 8, 2011
Messages
1,074
:)
If you're not sure what that all means why not post a cct diagram, which should include the required currents and voltages, and specifications of the transformer you intend to use.
We could tell you what it needs and how to connect it all up.
 
Last edited:

vick5821

Jan 22, 2012
700
Joined
Jan 22, 2012
Messages
700
I used a 6V transformer. And I want to step it from 240V to 6V. Unloaded means how ? the 10k consider as load ? how can I achieve near to 6V for the load ?

Thank you
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
The best way is to use a regulator. Resistors won't do it.
 

vick5821

Jan 22, 2012
700
Joined
Jan 22, 2012
Messages
700
we are not allowed to used regulator :( Just resistor and capacitor. Old time smoothing and filtering
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
And why didn't you post this in the homework help section?

It's not like you're new around here...
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
But if you post your homework in the wrong section you indicate to me that you want answers without doing any work yourself.

It doesn't make me want to assist you.
 

poor mystic

Apr 8, 2011
1,074
Joined
Apr 8, 2011
Messages
1,074
:)
Anyway, the point of the exercise is probably not for you to make a stable power supply but for you to exercise your mathematical wits to correctly design a filter to specifications laid down in class. That's what I'd teach, if anything.
 

poor mystic

Apr 8, 2011
1,074
Joined
Apr 8, 2011
Messages
1,074
:)
I presumed that a mathematical description of filter design had already been part of your course, and I apologise for any offense - .it's just that once you have such an understanding things get easier.
I may have over-estimated your intelligent laziness.
 

vick5821

Jan 22, 2012
700
Joined
Jan 22, 2012
Messages
700
I am trying now..I put 5 series diode after the rectification output and I get around 6.2 + V. Is this practical or appropiate ?
 

vick5821

Jan 22, 2012
700
Joined
Jan 22, 2012
Messages
700
ACtoDC.png
 
Top