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9V 1A schematic needed

I'm not an expert on power supplies, but this one shouldn't be too hard if it is just for some kind of home project or whatever.

Note that if you are designing a real power supply for a real product that has to get regulatory approval, then you may need expert advice.

The simplest way to build a power supply is to just use a transformer (put a fuse or two on the AC side of it), a bridge rectifier, some capacitors, and an LM317 (or something similar) with a big heatsink, and maybe another capacitor at the output.

Choosing the transformer voltage is a bit tricky. If it is too low, then the regulator will drop out of regulation and the output will ripple. If it is too high, then the regulator will dissipate too much power, and overheat. You might try a nominal 12 Volt transformer for a 9 Volt regulator.

Choosing capacitor values is a bit tricky, too. The bigger they are, the more they force the transformer into a low duty-cycle, high-current mode of operation. But if you don't have enough capacitor, then the Voltage will dip too low during the low part of the cycle, and the regulator will drop out.

Have fun.

--Mac

Reply to
Mac
Loading thread data ...

"John Woodgate" wrote in message news:+ snipped-for-privacy@jmwa.demon.co.uk...

That statement really makes no sense to me. How can you crowd the same charge transfer into less time and get its RMS value to decrease? (For conceptual simplification, assume the DC current taken from the bridge is constant, so that the charge, (Idc * (2 f)), is held constant.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
Reply to
Larry Brasfield

I read in sci.electronics.design that Mac wrote (in ) about '9V 1A schematic needed', on Sat, 19 Mar 2005:

In fact, the overall efficiency, measured as Idc/Irms, is higher at low rectifier conduction angles, even though the peak diode current is higher. A large filter capacitor doesn't increase transformer heating.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
There are two sides to every question, except 
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Reply to
John Woodgate

(Minor correction inserted in place below.) "Larry Brasfield" wrote in message news:QUX_d.14$ snipped-for-privacy@news.uswest.net...

the charge, (Idc / fc), is held constant. (Where 'fc' is 2 * line_frequency for a full-wave bridge, or 1 * line_frequency for a half-wave bridge.)

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
Reply to
Larry Brasfield

The DERF tranform, applied here, is described earlier in this thread.

"Fred Bloggs" wrote [DERF]

See my post at 12:10 on March 18.

I explained that already. See my post at 7:19 on March 19.

[DERF] 
--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
Reply to
Larry Brasfield

Looks like you're the one behind the curve. You seem to miss the point that his answer was of about the same characteristic relevance as all his other posts- he is a totally clueless nitwit, and any attempt at humor would be swamped by the overwhelming hot air, pretense, pseudo-theoretical factoid trash, and other elements of his style.

Reply to
Fred Bloggs

[...snip drivel from drowning rodent...]

Hey, loudmouth windbag, where are all the words on the noise induced detection problem in the 40khz amplifier thread? Your days of skulking off are over- and we are calling you due, pussy, phony, illiterate trash heap boy. Looks like you ran out of elementary factoid braindead arithmetic trash and now you are be called on it- You just don't seem to be taking up the challenge, mainly because you have run out of material- not so verbose when you have to actually produce something tangible are you, punk programmer, pseudo-intellectual, and pretentious fraud that you are....like I say, you are a drowning rodent.

Reply to
Fred Bloggs

What's really laughable is how you similarly stupid people can understand each other so well- sort of like pedophiles and other sociopathic deviants, you all know each other instinctively. Someone with your posting history is no position to laugh at anything. You are right about one thing, you are a "F"ing"A".

Reply to
Fred Bloggs

This has been converted, via a process I will call the DERF transform [1]. This elision process conforms to accepted Usenet quoting practise with the exception that elided text is replaced by "[DERF]" and, where needed for grammaticality, short sequences with a '[]' pair are inserted.

[1. Application of a filter removing Dreck, Extraneousness, Redundancy, Foolishness.]

"Fred Bloggs" wrote >

[DERF] (I am tempted to refine the DERF notation so that ridiculous amounts cut repetition are indicated.)

Fred, you need help. Or your meds. Or both. Settle down and try to remember how it was to resemble a normal person, if you can.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
Reply to
Larry Brasfield

The DERF tranform, applied here, is described earlier in this thread.

"Fred Bloggs" wrote >> I explained that already. See my post at 7:19 on March 19.

[DERF]

No, Fred, I am not dropping it all. As anyone with the brains God gave turnips can see, you are not responding to it except with garbage removed by the DERF transform. Do you truly find it so hard to devise a rational argument, or do you see your role here as mere pontification? Do you imagine that your garbage injections here do anything but make you ever more obviously a fool?

[DERF] 
--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
Reply to
Larry Brasfield

What's important (to me, at least) is that Fred, like a couple of other parties I could name, posts only to show how smart he is and how stupid everyone else is. His posts are generally delayed, which means he went to the trouble to do research before responding, which would be admirable except for the motivation.

What Fred et al never do is try to be genuinely helpful, social, whimsical, truly interested, creative, or fun.

So don't pay him undue attention: he's not nice and he's not important.

John

Reply to
John Larkin

I hope this means you fully recovered from whatever shock you suffered on account of my application of the inverse-DERF transform to what would have been empty text otherwise. I would like to know that, with a little research, you were able to discern its meaning.

Please drop me a line by email if you would like any further clarification, mitigation, or a real apology.

[Frivolity cut.] [Off-point old quotes cut.] [Fred-dreck cut.] 
--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
Reply to
Larry Brasfield

I read in sci.electronics.design that Roger Lascelles wrote (in ) about '9V 1A schematic needed', on Sat, 19 Mar 2005:

I based my statement on theoretical calculations, so simulations may provide somewhat different results.

Agreed. Do you find that leakage inductance has a significant effect?

A real mug's game, that is! 1 volt per farad, or thereabouts.

Yes, it does. I've done a lot of analysis of these circuits in connection with the famous IEC/EN 61000-3-2 standard on mains harmonic emissions.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
There are two sides to every question, except 
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Reply to
John Woodgate
[snip]

(1) I doubt seriously if Fred HAS a wife, but he is, at the very minimum, mentally deranged.

(2) I resent your mis-use of the term "Old Timer"... a great many of the posters here are Old Timers... I just passed the conventional age of retirement in the US, but have no intent of ever retiring.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

[snip]

Fred has a mental disorder. I doubt that it is the product of just old age.

My suspicion is that he is off his Lithium ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

Now John, IIRC you're just a year or so older then I am. (If you're having trouble with the math I just did my 16-1/4 birthday (base 4 :)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

Oh tee-hee-hee-heee. hey look at how clever Laweee Brathfeld is every body- [ yell that with lisp and childish voice....]

Where's your workup on the 40kHz amplifier thread, fairy loudmouth boy? Can't go any further with 4KTRB and some other simple-minded trash? We are not surprised, windbag. You are one little superficial and worthless moron.

Reply to
Fred Bloggs

Ooooh- deep, deep, question, superficial little piss ant boy and pretentious moron...Where's your workup on the 40kHz amplifier thread, fairy loudmouth boy? Can't go any further with 4KTRB and some other simple-minded trash? We are not surprised, windbag. You are one little superficial and worthless moron.

Reply to
Fred Bloggs

'Tweren't any this year, that's why the 1/4 ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

Did ya' figure that out, retard? Where's your workup on the 40kHz amplifier thread, fairy loudmouth boy? Can't go any further with 4KTRB and some other simple-minded trash? We are not surprised, windbag. You are one little superficial and worthless moron.

Reply to
Fred Bloggs

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