two switcher circuits

Guest
https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0







--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On 2020-04-03 10:34, jlarkin@highlandsniptechnology.com wrote:
https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0

Cute. Sure is going to need some input filtering though!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Fri, 3 Apr 2020 11:09:33 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 10:34, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0


Cute. Sure is going to need some input filtering though!

Cheers

Phil Hobbs

I have to resist the temptation to put bypass caps across voltage
sources in Spice. The LTM8078 apparently has inductors but no caps.
Even that is impressive. Can anybody x-ray one for me?

https://www.dropbox.com/s/b6dogwrwioka5nj/LTMs_Top.jpg?raw=1

https://www.dropbox.com/s/m1u04ne0w575ykl/LTMs_Bot.jpg?raw=1





--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:
https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0

Not a switcher, but expedient:

<https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0>
 
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0

Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.






--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On Fri, 03 Apr 2020 11:48:20 -0700, John Larkin wrote:

On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?
dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to laser
blast the anodize for external artwork.

Who made those boxes for you? I have an upcoming project where I
need something similar.

--
Chisolm
Texas-American
 
On Fri, 03 Apr 2020 14:10:06 -0500, Joe Chisolm
<jchisolm6@earthlink.net> wrote:

On Fri, 03 Apr 2020 11:48:20 -0700, John Larkin wrote:

On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?
dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to laser
blast the anodize for external artwork.

Who made those boxes for you? I have an upcoming project where I
need something similar.

https://www.pumay-aluminum.com/products/

They cut one of their extrusions to length and machined it per our
drawing. The blue anodize color is a little garish, so we'll ask them
to tone it down a bit next time.

The holes are drilled/tapped after anodize, so are conductive and
don't have the problems that the self-tappers do on the Hammond boxes.
Like metal shavings everywhere and stripped screws.

We add a couple of metal bars inside that the board bolts to.

https://www.dropbox.com/s/1fglmrtg3l9pkf8/J002_1.jpg?raw=1


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On 4/3/2020 2:48 PM, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

I noticed that the LM317 is OK with its input sitting about 4-5" from
the +/-50 switcher output filter caps, but without some extra filtering
closer to the regulator the LM337 is unhappy about it and starts
oscillating at low frequency

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.

Hammond makes some nice transformers at reasonable prices for e.g.
vacuum tube amps but their enclosures sure are drab!
 
On 2020-04-03 14:48, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

My eyes! My eyes!
The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.

Yeah, it would be good to get them to tone it down a bit. ;)

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On 2020-04-03 17:16, bitrex wrote:
On 4/3/2020 2:48 PM, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

I noticed that the LM317 is OK with its input sitting about 4-5" from
the +/-50 switcher output filter caps, but without some extra filtering
closer to the regulator the LM337 is unhappy about it and starts
oscillating at low frequency

The 337's pass transistor is an NPN, so its output is via the collector,
much like modern LDOs. It's a perfectly good part when used as
directed, but far less forgiving than the emitter-follower 317.

And tsk tsk on using those parts from a 50V supply--or are you using the
HV variants? (IDK if there's any difference apart from testing, of course.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Fri, 3 Apr 2020 17:54:54 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 14:48, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

My eyes! My eyes!

Get serious, I'm only running 2 mA in that LED. We were wondering how
it would look, just the led on the PCB and a hole drilled into the end
plate. The light bounces around in the hole and it actually looks
pretty good from all angles. Don't need no light pipe.

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.

Yeah, it would be good to get them to tone it down a bit. ;)

Cheers

Phil Hobbs

I kinda like it, but some other people here don't. The Chinese seem to
like bright primary colors, and it generally looks good on them.

We're investigating getting a 20-watt n/c fiber laser to blast the
lettering in-house.

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On 2020-04-03 18:23, John Larkin wrote:
On Fri, 3 Apr 2020 17:54:54 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 14:48, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

My eyes! My eyes!

Get serious, I'm only running 2 mA in that LED. We were wondering how
it would look, just the led on the PCB and a hole drilled into the end
plate. The light bounces around in the hole and it actually looks
pretty good from all angles. Don't need no light pipe.

It's the case I'm referring to. I might have a low threshold, but
electric blue anodize screams "aliexpress" to me. Of course, we're
still using the black Hammond boxes round here, so perhaps it's my inner
Amishman talking. ;)

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.

Yeah, it would be good to get them to tone it down a bit. ;)

Cheers

Phil Hobbs

I kinda like it, but some other people here don't. The Chinese seem to
like bright primary colors, and it generally looks good on them.

We're investigating getting a 20-watt n/c fiber laser to blast the
lettering in-house.

Fun.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Friday, April 3, 2020 at 5:55:02 PM UTC-4, Phil Hobbs wrote:
On 2020-04-03 14:48, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

My eyes! My eyes!

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.

Yeah, it would be good to get them to tone it down a bit. ;)

What part number is this? What color specification?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
On Fri, 3 Apr 2020 18:39:51 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 18:23, John Larkin wrote:
On Fri, 3 Apr 2020 17:54:54 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 14:48, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

My eyes! My eyes!

Get serious, I'm only running 2 mA in that LED. We were wondering how
it would look, just the led on the PCB and a hole drilled into the end
plate. The light bounces around in the hole and it actually looks
pretty good from all angles. Don't need no light pipe.

It's the case I'm referring to.

Oh, I knew that.

I might have a low threshold, but
electric blue anodize screams "aliexpress" to me. Of course, we're
still using the black Hammond boxes round here, so perhaps it's my inner
Amishman talking. ;)

We found the Hammonds to be mechanically messy too. They don't always
saw the ends off the extrusions at a 90 degree angle.

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to
laser blast the anodize for external artwork.

Yeah, it would be good to get them to tone it down a bit. ;)

Cheers

Phil Hobbs

I kinda like it, but some other people here don't. The Chinese seem to
like bright primary colors, and it generally looks good on them.

We're investigating getting a 20-watt n/c fiber laser to blast the
lettering in-house.

Fun.

Cheers

Phil Hobbs
--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On 4/4/20 7:23 am, John Larkin wrote:
On Fri, 03 Apr 2020 14:10:06 -0500, Joe Chisolm
jchisolm6@earthlink.net> wrote:

On Fri, 03 Apr 2020 11:48:20 -0700, John Larkin wrote:

On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?
dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to laser
blast the anodize for external artwork.

Who made those boxes for you? I have an upcoming project where I
need something similar.

https://www.pumay-aluminum.com/products/

Very nice.

The holes are drilled/tapped after anodize, so are conductive and
don't have the problems that the self-tappers do on the Hammond boxes.
Like metal shavings everywhere and stripped screws.

Never ever use self-tappers. They work loose with vibration, and cut new
paths when you re-insert them. You don't even need to tap if you use
trilobular (thread-forming) screws. Taptite is one brand, but it's a DIN
standard.

CH
 
On 4/3/2020 6:16 PM, Phil Hobbs wrote:
On 2020-04-03 17:16, bitrex wrote:
On 4/3/2020 2:48 PM, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0









Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

I noticed that the LM317 is OK with its input sitting about 4-5" from
the +/-50 switcher output filter caps, but without some extra
filtering closer to the regulator the LM337 is unhappy about it and
starts oscillating at low frequency

The 337's pass transistor is an NPN, so its output is via the collector,
much like modern LDOs.  It's a perfectly good part when used as
directed, but far less forgiving than the emitter-follower 317.

And tsk tsk on using those parts from a 50V supply--or are you using the
HV variants?  (IDK if there's any difference apart from testing, of
course.)

Cheers

Phil Hobbs

The input-output voltage differential on the top and bottom 317 and 337
exceeds the 40V limit for about 200 microseconds on startup with the
+/-50 rails coming up in the sim way faster than they actually would
IRL. I think it'll be okay. It's not going into production it's a
place-holder to test the main board until I can get around to buying or
building a PS that doesn't consume so much power for the client
 
On 4/3/2020 8:47 PM, bitrex wrote:
On 4/3/2020 6:16 PM, Phil Hobbs wrote:
On 2020-04-03 17:16, bitrex wrote:
On 4/3/2020 2:48 PM, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0









Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

I noticed that the LM317 is OK with its input sitting about 4-5" from
the +/-50 switcher output filter caps, but without some extra
filtering closer to the regulator the LM337 is unhappy about it and
starts oscillating at low frequency

The 337's pass transistor is an NPN, so its output is via the
collector, much like modern LDOs.  It's a perfectly good part when
used as directed, but far less forgiving than the emitter-follower 317.

And tsk tsk on using those parts from a 50V supply--or are you using
the HV variants?  (IDK if there's any difference apart from testing,
of course.)

Cheers

Phil Hobbs


The input-output voltage differential on the top and bottom 317 and 337
exceeds the 40V limit for about 200 microseconds on startup with the
+/-50 rails coming up in the sim way faster than they actually would
IRL. I think it'll be okay. It's not going into production it's a
place-holder to test the main board until I can get around to buying or
building a PS that doesn't consume so much power for the client

Shipments are suffering delays to my location and my girlfriend is in
our home in another state (RI) that's banned non-essential cross-border
traffic, I'm not a RI resident, and they're busting and fining people
they seem to be serious about it. let the Constitutional scholars fight
over it later.

some of my gear is stuck there, while I'm working on caring for an
elderly parent up here at home in MA, no way she's staying some other
place right now.

Doing some under-the-gun engineering here lol
 
On Sat, 4 Apr 2020 10:58:32 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 4/4/20 7:23 am, John Larkin wrote:
On Fri, 03 Apr 2020 14:10:06 -0500, Joe Chisolm
jchisolm6@earthlink.net> wrote:

On Fri, 03 Apr 2020 11:48:20 -0700, John Larkin wrote:

On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?
dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to laser
blast the anodize for external artwork.

Who made those boxes for you? I have an upcoming project where I
need something similar.

https://www.pumay-aluminum.com/products/

Very nice.

The holes are drilled/tapped after anodize, so are conductive and
don't have the problems that the self-tappers do on the Hammond boxes.
Like metal shavings everywhere and stripped screws.

Never ever use self-tappers. They work loose with vibration, and cut new
paths when you re-insert them. You don't even need to tap if you use
trilobular (thread-forming) screws. Taptite is one brand, but it's a DIN
standard.

CH

People extrude 3/4 holes in things like this, and then use
self-tapping screws. The partial holes tend to break taps.




--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On 4/4/20 3:16 pm, jlarkin@highlandsniptechnology.com wrote:
On Sat, 4 Apr 2020 10:58:32 +1100, Clifford Heath <no.spam@please.net
wrote:

On 4/4/20 7:23 am, John Larkin wrote:
On Fri, 03 Apr 2020 14:10:06 -0500, Joe Chisolm
jchisolm6@earthlink.net> wrote:

On Fri, 03 Apr 2020 11:48:20 -0700, John Larkin wrote:

On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?
dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

The idea is to get away from the boring Hammond boxes. This is a
semi-custom extrusion with nice grounding and thermals. We plan to laser
blast the anodize for external artwork.

Who made those boxes for you? I have an upcoming project where I
need something similar.

https://www.pumay-aluminum.com/products/

Very nice.

The holes are drilled/tapped after anodize, so are conductive and
don't have the problems that the self-tappers do on the Hammond boxes.
Like metal shavings everywhere and stripped screws.

Never ever use self-tappers. They work loose with vibration, and cut new
paths when you re-insert them. You don't even need to tap if you use
trilobular (thread-forming) screws. Taptite is one brand, but it's a DIN
standard.

CH

People extrude 3/4 holes in things like this, and then use
self-tapping screws.

People don't make things to be serviced. Self-tappers can be ok in the
absence of vibration or the need to service.

> The partial holes tend to break taps.

Tapping deep holes in Al is fraught - the correct technique involves
lots of reversals, and in large sizes, multiple passes with different
taps, so it's slow.

CH
 
On 2020-04-03 19:27, John Larkin wrote:
On Fri, 3 Apr 2020 18:39:51 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 18:23, John Larkin wrote:
On Fri, 3 Apr 2020 17:54:54 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-04-03 14:48, John Larkin wrote:
On Fri, 3 Apr 2020 13:31:31 -0400, bitrex <user@example.net> wrote:

On 4/3/2020 10:34 AM, jlarkin@highlandsniptechnology.com wrote:


https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0

https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0








Not a switcher, but expedient:

https://www.dropbox.com/s/uf29ubm0v1ox7pv/linear_tracking.PNG?dl=0


Driving the adj pin of a 3t regulator is an under-appreciated trick.
They are nice, cheap, thermally limited power amps.

We have standardized on 24 volt warts for small boxes, so we want to
switch mostly. So multiple outputs from tiny switchers is good.

Just minutes ago I got this:

https://www.dropbox.com/s/wxerjg36c3ow8s5/J744_3.jpg?dl=0

https://www.dropbox.com/s/lnn1jwk7gm1h713/J744_2.jpg?dl=0

My eyes! My eyes!

Get serious, I'm only running 2 mA in that LED. We were wondering how
it would look, just the led on the PCB and a hole drilled into the end
plate. The light bounces around in the hole and it actually looks
pretty good from all angles. Don't need no light pipe.

It's the case I'm referring to.

Oh, I knew that.

I might have a low threshold, but
electric blue anodize screams "aliexpress" to me. Of course, we're
still using the black Hammond boxes round here, so perhaps it's my inner
Amishman talking. ;)

We found the Hammonds to be mechanically messy too. They don't always
saw the ends off the extrusions at a 90 degree angle.

That could be bad. I haven't seen that problem from them, but maybe
I've managed to avoid Monday morning boxes. ;)

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 

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