Surprised by power supply design

[BFoelsch]

I ordered a 13.8 volt, 4 amp power supply (battery eliminator) from one of
the "tier 2" manufacturers of such stuff. (BK Precision)

Anyway, I received this thing, it works fine and meets all specs, but I was
shocked to find out that this is a linear power supply! Stranger yet, it is
completely discrete, not an IC in it.

I had kind of suspected that at the $40 price point I would get something a
bit less, uh, heavy. but it has a genuine 50/60 Hz transformer in it.

Isn't this a bit odd in 2004? I expected a switcher, or perhaps a linear
with a 1 package regulation solution.

Any opinions?

 

[Rich Grise]

On Tue, 28 Dec 2004 15:19:08 -0500, BFoelsch wrote:

I ordered a 13.8 volt, 4 amp power supply (battery eliminator) from one of
the "tier 2" manufacturers of such stuff. (BK Precision)

Anyway, I received this thing, it works fine and meets all specs, but I was
shocked to find out that this is a linear power supply! Stranger yet, it is
completely discrete, not an IC in it.

I had kind of suspected that at the $40 price point I would get something a
bit less, uh, heavy. but it has a genuine 50/60 Hz transformer in it.

Isn't this a bit odd in 2004? I expected a switcher, or perhaps a linear
with a 1 package regulation solution.

Any opinions?

My opinion is that you're very lucky! Did you happen to notice if the
tranny is ferroresonant? That makes the regulator a lot cheaper, like you
don't need one at all. ;-) The circuitry is probably just timers and
protection, if it is a ferro.

Cheers!
Rich

 

[Rich Grise]

On Tue, 28 Dec 2004 20:52:28 +0000, John Woodgate wrote:

4. Being heavy, a linear really FEELS like a bargain for $40. (;-)

Goldbloom: "Is it heavy?"
Kid: "Yeah."
Goldbloom: "Then it's expensive. Put it back."

Cheers!
Rich

 

[John Woodgate]

I read in sci.electronics.design that Rich Grise <richgrise@example.net>
wrote (in <pan.2004.12.29.00.15.07.583735@example.net&gt about 'Surprised
by power supply design', on Wed, 29 Dec 2004:

On Tue, 28 Dec 2004 20:52:28 +0000, John Woodgate wrote:

4. Being heavy, a linear really FEELS like a bargain for $40. (;-)

Goldbloom: "Is it heavy?"
Kid: "Yeah."
Goldbloom: "Then it's expensive. Put it back."

Goldbloom doesn't distinguish between 'costly' and 'expensive'. $20k is

costly, but it's not expensive if it's a new Cadillac!
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[me]

3. If the extra mass of the linear is not an issue, the switcher has
few advantages.

I had always figured that eliminating the cost of a mains frequency
transformer was one of them.

Switching transformers are generally more expensive.

 

[Fred Bloggs]

BFoelsch wrote:

I ordered a 13.8 volt, 4 amp power supply (battery eliminator) from one of
the "tier 2" manufacturers of such stuff. (BK Precision)

Anyway, I received this thing, it works fine and meets all specs, but I was
shocked to find out that this is a linear power supply! Stranger yet, it is
completely discrete, not an IC in it.

I had kind of suspected that at the $40 price point I would get something a
bit less, uh, heavy. but it has a genuine 50/60 Hz transformer in it.

Isn't this a bit odd in 2004? I expected a switcher, or perhaps a linear
with a 1 package regulation solution.

Any opinions?

That thing, or its major subassemblies, may have been manufactured back
in 1990.

 

[martin griffith]

On Wed, 29 Dec 2004 00:08:42 GMT, in sci.electronics.design Rich Grise
<richgrise@example.net> wrote:

On Tue, 28 Dec 2004 15:19:08 -0500, BFoelsch wrote:

I ordered a 13.8 volt, 4 amp power supply (battery eliminator) from one of
the "tier 2" manufacturers of such stuff. (BK Precision)

Anyway, I received this thing, it works fine and meets all specs, but I was
shocked to find out that this is a linear power supply! Stranger yet, it is
completely discrete, not an IC in it.

I had kind of suspected that at the $40 price point I would get something a
bit less, uh, heavy. but it has a genuine 50/60 Hz transformer in it.

Isn't this a bit odd in 2004? I expected a switcher, or perhaps a linear
with a 1 package regulation solution.

Any opinions?

My opinion is that you're very lucky! Did you happen to notice if the
tranny is ferroresonant? That makes the regulator a lot cheaper, like you
don't need one at all. ;-) The circuitry is probably just timers and
protection, if it is a ferro.

Cheers!
Rich

how do you spot a ferroresonant tranny?

martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

 

Pass a magnet over her makeup. If she starts to vibrate, you've struck
gold.

 

[martin griffith]

On 29 Dec 2004 06:19:56 -0800, in sci.electronics.design
larwe@larwe.com wrote:

Pass a magnet over her makeup. If she starts to vibrate, you've struck
gold.
hehe, that reminded me of BladeRunner for some unknown reason

Happy New Year!




martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.