Re: Re:_[sdiy]_+-12V_supply

[Scott Gravenhorst]

=?iso-8859-2?Q?Roman?= <modular at go2.pl> wrote:
>you're right, telling that something sucks may be offending to milions of people using it.
>So to make it more specific, here's my explanation why they suck:
>- it would be a bit tricky to achieve +/-1mV accuracy from them
>- they have considerable load and line regulation (not a big 
>problem if you have constant load and stable power line) - they 
>have considerably high quiescent current, not acceptable for 
>battery operation. 
>
>fair enough?

Yes, this is good and it makes sense now.  

It also leaves open many many applications that _can_ use them.  For me, if I need an accurate
voltage reference, I will use a reference voltage IC or a zener to create the voltage I need.  In
my little world, I don't worry about highly accurate rails when I don't actually need them.  It
makes the power supply more expensive for nothing.



>---- Wiadomo¶æ Oryginalna ----
>Od: James Patchell <patchell at cox.net>
>Do: synth-diy at dropmix.xs4all.nl
>Data: Fri, 14 Jan 2005 16:45:06 -0800
>Temat: Re:_[sdiy]_+-12V_supply
>
>> Making blanket statements about parts sucking always cracks me up.  Since 
>> the 78xx/79xx regulators are the biggest selling regulators, that either 
>> means everybody is stupid, or the parts must have true value.  I have run 
>> into a few engineers who felt the same way.  After fixing their mistakes, 
>> the parts have always worked flawlessly.  There are applications where they 
>> will not work.  I think I have only encountered one of those in 30 years....
>> 
>> At 07:02 AM 1/14/2005 -0700, Scott Gravenhorst wrote:
>> >=?iso-8859-2?Q?Roman?= <modular at go2.pl> wrote:
>> > >if putting 723 instead of 7812 is an overkill, how would you call
>> > >someone who made 1.5A power supply using regular opamps,
>> > >darlington transistors, lots of other components, and 10ppm/K
>> > >reference IC, where LM317/337 would be more than enough?
>> > >
>> > >You're right, a crazy maniac.
>> > >But I just wanted it so bad.
>> > >
>> > >BTW, IMHO 78xx and 79xx suck
>> > >
>> > >Roman
>> >
>> >Hmm.  Well, everyone is entitled to an opinion, I use 78xx and 79xx
>> >and I don't have problems with them.  I just don't hear the noise
>> >that they're supposed to make.  Not only do I use these nasty 3
>> >terminal regulators, I use them with AC wallwarts and halfwave
>> >rectifiers.
>> >
>> > >
>> > >---- Wiadomo¶æ Oryginalna ----
>> > >Od: "Roy J. Tellason" <rtellason at blazenet.net>
>> > >Do: synth <synth-diy at dropmix.xs4all.nl>
>> > >Data: Thu, 13 Jan 2005 20:50:36 -0500
>> > >Temat: Re: [sdiy] +-12V supply
>> > >
>> > >> On Thursday 13 January 2005 06:55 pm, Chris CROSSKEY wrote:
>> > >> >  Toss out the 7812/7912 and use a 723 on each side with a big bypass
>> > >> > transistor.....
>> > >>
>> > >> Why,  if the simpler setup will do what you need?  Did I miss 
>> > something there
>> > >> that indicated a massive current draw requirement or something?
>> > >>
>> > >
>> > >
>> >
>> >---------------------------------------------------------
>> >- Where merit is not rewarded, excellence fades.
>> >- Hydrogen is pointless without solar.
>> >- What good are laws that only lawyers understand?
>> >- The media's credibility should always be questioned.
>> >- The only good terrorist is a dead terrorist.
>> >- Governments do nothing well, save collect taxes.
>> >
>> >-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>> >-- Linux Rex         | RedWebMail by RedStarWare
>> >-- FatMan: home1.gte.net/res0658s/fatman/
>> >-- NonFatMan: home1.gte.net/res0658s/electronics/
>> >-- Autodidactic Master of Arcane and Hidden Knowledge.
>> 
>>          -Jim
>> ***************************************************************
>> http://www.oldcrows.net/~patchell
>> 
>> ***************************************************************
>> 
>> 
>> 
>> 
>

---------------------------------------------------------
- Where merit is not rewarded, excellence fades.
- Hydrogen is pointless without solar.
- What good are laws that only lawyers understand?
- The media's credibility should always be questioned.
- The only good terrorist is a dead terrorist.
- Governments do nothing well, save collect taxes.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- Autodidactic Master of Arcane and Hidden Knowledge.