https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1

My PCB guy is overloaded, so I've taken over my board layout, which is
another 3-phase alternator simulator. I enjoy doing a PCB layout now
and then.

Anyway, that's a floating power supply, +48 to isolated +-60 at about
200 watts. What's scary is that those purple logic traces on layer 6
transition from ground referenced (left of the Coilraft planar
transformer) to referenced to N, the isolated common and 3-phase
neutral, layer 5 split plane.

I love these things:

https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1

Coilcraft does great stuff.

On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
<jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:

>https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>
>My PCB guy is overloaded, so I've taken over my board layout, which is
>another 3-phase alternator simulator. I enjoy doing a PCB layout now
>and then.
>
>Anyway, that's a floating power supply, +48 to isolated +-60 at about
>200 watts. What's scary is that those purple logic traces on layer 6
>transition from ground referenced (left of the Coilraft planar
>transformer) to referenced to N, the isolated common and 3-phase
>neutral, layer 5 split plane.
>
>I love these things:
>
>https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>
>Coilcraft does great stuff.

When I need a transformer I just wind one...
https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
the math is simple
https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg

On 2023/11/26 8:34 a.m., Jan Panteltje wrote:
> On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
> <jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>
>> https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>
>> My PCB guy is overloaded, so I've taken over my board layout, which is
>> another 3-phase alternator simulator. I enjoy doing a PCB layout now
>> and then.
>>
>> Anyway, that's a floating power supply, +48 to isolated +-60 at about
>> 200 watts. What's scary is that those purple logic traces on layer 6
>> transition from ground referenced (left of the Coilraft planar
>> transformer) to referenced to N, the isolated common and 3-phase
>> neutral, layer 5 split plane.
>>
>> I love these things:
>>
>> https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>
>> Coilcraft does great stuff.
>
> When I need a transformer I just wind one...
> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
> the math is simple
> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg

Damn, another Rabbit Hole!

Transformers...the headache (hard to find) of restoration of jukeboxes
and some pinball games - so now, thanks John & Jan!, I'm looking at
lamination and bobbin suppliers and thinking of building my own...

https://ascocomponents.co.uk/laminations/ei-laminations/

https://www.leswilliams.co.uk/products/transformer-bobbins

Why are these people all in the UK?

John ;-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
#7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

John Robertson <jrr@flippers.com> wrote:
> On 2023/11/26 8:34 a.m., Jan Panteltje wrote:
>> On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>> <jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>
>>> https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>
>>> My PCB guy is overloaded, so I've taken over my board layout, which is
>>> another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>> and then.
>>>
>>> Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>> 200 watts. What's scary is that those purple logic traces on layer 6
>>> transition from ground referenced (left of the Coilraft planar
>>> transformer) to referenced to N, the isolated common and 3-phase
>>> neutral, layer 5 split plane.
>>>
>>> I love these things:
>>>
>>> https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>
>>> Coilcraft does great stuff.
>>
>> When I need a transformer I just wind one...
>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>> the math is simple
>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>
> Damn, another Rabbit Hole!
>
> Transformers...the headache (hard to find) of restoration of jukeboxes
> and some pinball games - so now, thanks John & Jan!, I'm looking at
> lamination and bobbin suppliers and thinking of building my own...
>
> https://ascocomponents.co.uk/laminations/ei-laminations/
>
> https://www.leswilliams.co.uk/products/transformer-bobbins
>
> Why are these people all in the UK?
>
> John ;-#)#
>

The Lucas replacement market.

Cheers

Phil “former Triumph owner” Hobbs

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

On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

>On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
><jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>
>>https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>
>>My PCB guy is overloaded, so I've taken over my board layout, which is
>>another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>and then.
>>
>>Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>200 watts. What's scary is that those purple logic traces on layer 6
>>transition from ground referenced (left of the Coilraft planar
>>transformer) to referenced to N, the isolated common and 3-phase
>>neutral, layer 5 split plane.
>>
>>I love these things:
>>
>>https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>
>>Coilcraft does great stuff.
>
>When I need a transformer I just wind one...
> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>the math is simple
> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg

The math of ordering a standard part is simpler. And the parts cost
about 1/20 as much.

I only design what I can't buy. Weird stuff. I've never seen a
transmission-line transformer for sale, or maybe inside a big metal
box.

Incidentally, Coilcraft does custom versions of that planar
transformer.

For modest numbers of turns, you can make the windings on your PC
board and optionally snap a ferrite core onto both sides of the board.
Still a hassle.

I was wondering about using two halves of a pot core, bolted on to the
board, with the FR4 making a rather large air gap.

On 11/26/23 20:24, John Larkin wrote:
> On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
> wrote:
>
>> On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>> <jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>
>>> https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>
>>> My PCB guy is overloaded, so I've taken over my board layout, which is
>>> another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>> and then.
>>>
>>> Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>> 200 watts. What's scary is that those purple logic traces on layer 6
>>> transition from ground referenced (left of the Coilraft planar
>>> transformer) to referenced to N, the isolated common and 3-phase
>>> neutral, layer 5 split plane.
>>>
>>> I love these things:
>>>
>>> https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>
>>> Coilcraft does great stuff.
>>
>> When I need a transformer I just wind one...
>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>> the math is simple
>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>
> The math of ordering a standard part is simpler. And the parts cost
> about 1/20 as much.
>
> I only design what I can't buy. Weird stuff. I've never seen a
> transmission-line transformer for sale, or maybe inside a big metal
> box.
> [...]

Mini-circuits sells what are basically Ruthroff-type transmission
line transformers in dip or SMD packages. They are wound with wire.

I've never seen a bare transformer wound with coaxial cable for sale.
(Unless you want to include some quarter-wave dielectric resonators
into your definition of transformers.) They always seem to come in
connectorized metal boxes. I've made plenty myself though. Once in
a while is fine, but you don't want to have to do it in production
quantities.

Jeroen Belleman

On Sun, 26 Nov 2023 20:58:31 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 11/26/23 20:24, John Larkin wrote:
>> On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
>> wrote:
>>
>>> On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>>> <jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>>
>>>> https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>>
>>>> My PCB guy is overloaded, so I've taken over my board layout, which is
>>>> another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>>> and then.
>>>>
>>>> Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>>> 200 watts. What's scary is that those purple logic traces on layer 6
>>>> transition from ground referenced (left of the Coilraft planar
>>>> transformer) to referenced to N, the isolated common and 3-phase
>>>> neutral, layer 5 split plane.
>>>>
>>>> I love these things:
>>>>
>>>> https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>>
>>>> Coilcraft does great stuff.
>>>
>>> When I need a transformer I just wind one...
>>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>>> the math is simple
>>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>>
>> The math of ordering a standard part is simpler. And the parts cost
>> about 1/20 as much.
>>
>> I only design what I can't buy. Weird stuff. I've never seen a
>> transmission-line transformer for sale, or maybe inside a big metal
>> box.
> > [...]
>
>Mini-circuits sells what are basically Ruthroff-type transmission
>line transformers in dip or SMD packages. They are wound with wire.
>
>I've never seen a bare transformer wound with coaxial cable for sale.
>(Unless you want to include some quarter-wave dielectric resonators
>into your definition of transformers.) They always seem to come in
>connectorized metal boxes. I've made plenty myself though. Once in
>a while is fine, but you don't want to have to do it in production
>quantities.
>
>Jeroen Belleman

We have a few products that use transmission-line transformers, which
we make. This is on the high-voltage option of our P500 digital delay
generator:

https://www.dropbox.com/s/pmecggbi463ipes/TX_1.jpg?raw=1

The connectorized cable is a stock part and the connectors are SMT on
the board, so it's fairly easy to assemble.

Dielectric resonators are usually shorted on one end, and tend to be
crazy low impedances as tx lines, like 10 ohms.

On Sun, 26 Nov 2023 12:30:10 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Sun, 26 Nov 2023 20:58:31 +0100, Jeroen Belleman
><jeroen@nospam.please> wrote:
>
>>On 11/26/23 20:24, John Larkin wrote:
>>> On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
>>> wrote:
>>>
>>>> On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>>>> <jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>>>
>>>>> <https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1>
>>>>>
>>>>> My PCB guy is overloaded, so I've taken over my board layout, which is
>>>>> another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>>>> and then.
>>>>>
>>>>> Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>>>> 200 watts. What's scary is that those purple logic traces on layer 6
>>>>> transition from ground referenced (left of the Coilraft planar
>>>>> transformer) to referenced to N, the isolated common and 3-phase
>>>>> neutral, layer 5 split plane.
>>>>>
>>>>> I love these things:
>>>>>
>>>>> <https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1>
>>>>>
>>>>> Coilcraft does great stuff.
>>>>
>>>> When I need a transformer I just wind one...
>>>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>>>> the math is simple
>>>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>>>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>>>
>>> The math of ordering a standard part is simpler. And the parts cost
>>> about 1/20 as much.
>>>
>>> I only design what I can't buy. Weird stuff. I've never seen a
>>> transmission-line transformer for sale, or maybe inside a big metal
>>> box.
>> > [...]
>>
>>Mini-circuits sells what are basically Ruthroff-type transmission
>>line transformers in dip or SMD packages. They are wound with wire.
>>
>>I've never seen a bare transformer wound with coaxial cable for sale.
>>(Unless you want to include some quarter-wave dielectric resonators
>>into your definition of transformers.) They always seem to come in
>>connectorized metal boxes. I've made plenty myself though. Once in
>>a while is fine, but you don't want to have to do it in production
>>quantities.
>>
>>Jeroen Belleman
>
>We have a few products that use transmission-line transformers, which
>we make. This is on the high-voltage option of our P500 digital delay
>generator:
>
><https://www.dropbox.com/s/pmecggbi463ipes/TX_1.jpg?raw=1>
>
>The connectorized cable is a stock part and the connectors are SMT on
>the board, so it's fairly easy to assemble.
>
>Dielectric resonators are usually shorted on one end, and tend to be
>crazy low impedances as tx lines, like 10 ohms.

I did find one manufacturer of Ruthroff-type transmission line
transformers, serving the IEEE 802.3 manufacturer market, but the
price was ruinous, and the manufacturer annoying, so I documented in
the standard how to make a suitable transformer by winding a ferrite
toroid core with extruded solid copper shield semi rigid coax without
the shields shorting together. It isn't hard, and there are only five
or ten turns, so it was perfectly practical to make these
transformers. Quantity was too small to justify anything more
complex. This has to have been twenty years ago.

Joe Gwinn

On a sunny day (Sun, 26 Nov 2023 11:24:14 -0800) it happened John Larkin
<jl@997PotHill.com> wrote in <tc67mipuqp22ja3o24pu3n5k01ofmavihb@4ax.com>:

>On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>><jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>
>>>https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>
>>>My PCB guy is overloaded, so I've taken over my board layout, which is
>>>another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>>and then.
>>>
>>>Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>>200 watts. What's scary is that those purple logic traces on layer 6
>>>transition from ground referenced (left of the Coilraft planar
>>>transformer) to referenced to N, the isolated common and 3-phase
>>>neutral, layer 5 split plane.
>>>
>>>I love these things:
>>>
>>>https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>
>>>Coilcraft does great stuff.
>>
>>When I need a transformer I just wind one...
>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>>the math is simple
>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>
>The math of ordering a standard part is simpler. And the parts cost
>about 1/20 as much.
>
>I only design what I can't buy. Weird stuff. I've never seen a
>transmission-line transformer for sale, or maybe inside a big metal
>box.
>
>Incidentally, Coilcraft does custom versions of that planar
>transformer.
>
>For modest numbers of turns, you can make the windings on your PC
>board and optionally snap a ferrite core onto both sides of the board.
>Still a hassle.
>
>I was wondering about using two halves of a pot core, bolted on to the
>board, with the FR4 making a rather large air gap.

That would also break the outside magnetic coupling,
so basically get you very little core effect.
Normally in a potcore with airgap only the inner part is shorter, touches less.
? Potcores are nice.
https://panteltje.nl/pub/8052AH_BASIC_computer/8052AH_BASIC_computer_inside_img_1727.jpg
eighties... EPROM programming voltage generator...
https://panteltje.nl/pub/8052AH_BASIC_computer/dc_dc_converter_detail/5V_to_30V_converter.jpg
almost a sinewave, no switcher noise...

On a sunny day (Sun, 26 Nov 2023 09:39:25 -0800) it happened John Robertson
<jrr@flippers.com> wrote in <ujvvsf$3bjt4$1@dont-email.me>:

>On 2023/11/26 8:34 a.m., Jan Panteltje wrote:
>> On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>> <jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>
>>> https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>
>>> My PCB guy is overloaded, so I've taken over my board layout, which is
>>> another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>> and then.
>>>
>>> Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>> 200 watts. What's scary is that those purple logic traces on layer 6
>>> transition from ground referenced (left of the Coilraft planar
>>> transformer) to referenced to N, the isolated common and 3-phase
>>> neutral, layer 5 split plane.
>>>
>>> I love these things:
>>>
>>> https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>
>>> Coilcraft does great stuff.
>>
>> When I need a transformer I just wind one...
>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>> the math is simple
>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>
>Damn, another Rabbit Hole!
>
>Transformers...the headache (hard to find) of restoration of jukeboxes
>and some pinball games - so now, thanks John & Jan!, I'm looking at
>lamination and bobbin suppliers and thinking of building my own...
>
>https://ascocomponents.co.uk/laminations/ei-laminations/
>
>https://www.leswilliams.co.uk/products/transformer-bobbins
>
>Why are these people all in the UK?
>
>John ;-#)#

You do not always _need_ a core..
https://panteltje.nl/pub/inductive_coupling_real_power_300Vpp_IMG_6092.JPG
that is a cheap ebay inductive heater with my home made coils.
Melting solder with it:
https://panteltje.nl/pub/carbon_crucible_power_off_IMG_5428.JPG
https://panteltje.nl/pub/crucible_stand_IMG_5440.JPG

Ringcores are also fun, bit more difficult to wind:
https://panteltje.nl/pub/power_to_drone_table_test_IMG_6260.JPG
that is a tuned oscillator, 60 W in that test, tuning is what all the parallel caps are for...
Induction is fun!

On Mon, 27 Nov 2023 03:29:31 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

>On a sunny day (Sun, 26 Nov 2023 11:24:14 -0800) it happened John Larkin
><jl@997PotHill.com> wrote in <tc67mipuqp22ja3o24pu3n5k01ofmavihb@4ax.com>:
>
>>On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
>>wrote:
>>
>>>On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>>><jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>>
>>>>https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>>
>>>>My PCB guy is overloaded, so I've taken over my board layout, which is
>>>>another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>>>and then.
>>>>
>>>>Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>>>200 watts. What's scary is that those purple logic traces on layer 6
>>>>transition from ground referenced (left of the Coilraft planar
>>>>transformer) to referenced to N, the isolated common and 3-phase
>>>>neutral, layer 5 split plane.
>>>>
>>>>I love these things:
>>>>
>>>>https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>>
>>>>Coilcraft does great stuff.
>>>
>>>When I need a transformer I just wind one...
>>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>>>the math is simple
>>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>>
>>The math of ordering a standard part is simpler. And the parts cost
>>about 1/20 as much.
>>
>>I only design what I can't buy. Weird stuff. I've never seen a
>>transmission-line transformer for sale, or maybe inside a big metal
>>box.
>>
>>Incidentally, Coilcraft does custom versions of that planar
>>transformer.
>>
>>For modest numbers of turns, you can make the windings on your PC
>>board and optionally snap a ferrite core onto both sides of the board.
>>Still a hassle.
>>
>>I was wondering about using two halves of a pot core, bolted on to the
>>board, with the FR4 making a rather large air gap.
>
>That would also break the outside magnetic coupling,
>so basically get you very little core effect.
>Normally in a potcore with airgap only the inner part is shorter, touches less.
>?
>Potcores are nice.
> https://panteltje.nl/pub/8052AH_BASIC_computer/8052AH_BASIC_computer_inside_img_1727.jpg
> eighties... EPROM programming voltage generator...
> https://panteltje.nl/pub/8052AH_BASIC_computer/dc_dc_converter_detail/5V_to_30V_converter.jpg
>almost a sinewave, no switcher noise...

That last one has a base bias scheme that is more subtle than it
looks.

I did the same thing, but with the feedback winding in the emitter,
for a gadget used on the C5A transport.

On a sunny day (Sun, 26 Nov 2023 22:19:15 -0800) it happened John Larkin
<jl@997PotHill.com> wrote in <p2d8mi93k4pcuvi6rqatb97a3j0r9vpss7@4ax.com>:

>On Mon, 27 Nov 2023 03:29:31 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Sun, 26 Nov 2023 11:24:14 -0800) it happened John Larkin
>><jl@997PotHill.com> wrote in <tc67mipuqp22ja3o24pu3n5k01ofmavihb@4ax.com>:
>>
>>>On Sun, 26 Nov 2023 16:34:15 GMT, Jan Panteltje <alien@comet.invalid>
>>>wrote:
>>>
>>>>On a sunny day (Sun, 26 Nov 2023 07:17:39 -0800) it happened John Larkin
>>>><jl@997PotHill.com> wrote in <odn6mi1b6p99mpku923anu2l7clbh7ejpo@4ax.com>:
>>>>
>>>>>https://www.dropbox.com/scl/fi/lujsxfrwlaiocsa2y7k60/P942_DC-DC_12.jpg?rlkey=jslmsa1si2kwbk3l00wph9dhe&raw=1
>>>>>
>>>>>My PCB guy is overloaded, so I've taken over my board layout, which is
>>>>>another 3-phase alternator simulator. I enjoy doing a PCB layout now
>>>>>and then.
>>>>>
>>>>>Anyway, that's a floating power supply, +48 to isolated +-60 at about
>>>>>200 watts. What's scary is that those purple logic traces on layer 6
>>>>>transition from ground referenced (left of the Coilraft planar
>>>>>transformer) to referenced to N, the isolated common and 3-phase
>>>>>neutral, layer 5 split plane.
>>>>>
>>>>>I love these things:
>>>>>
>>>>>https://www.dropbox.com/s/3d093msdmuinhxs/Coilcraft_PL300.jpg?raw=1
>>>>>
>>>>>Coilcraft does great stuff.
>>>>
>>>>When I need a transformer I just wind one...
>>>> https://panteltje.nl/pub/ultrasonic_antifouling_bigger_transformer_IMG_5179.JPG
>>>>the math is simple
>>>> https://panteltje.nl/pub/ultrasonic_anti_fouling_circuit_diagram_IMG_5144.JPG
>>>> https://panteltje.nl/pub/home_made_1_to_33_hv_transformer_img_3096.jpg
>>>
>>>The math of ordering a standard part is simpler. And the parts cost
>>>about 1/20 as much.
>>>
>>>I only design what I can't buy. Weird stuff. I've never seen a
>>>transmission-line transformer for sale, or maybe inside a big metal
>>>box.
>>>
>>>Incidentally, Coilcraft does custom versions of that planar
>>>transformer.
>>>
>>>For modest numbers of turns, you can make the windings on your PC
>>>board and optionally snap a ferrite core onto both sides of the board.
>>>Still a hassle.
>>>
>>>I was wondering about using two halves of a pot core, bolted on to the
>>>board, with the FR4 making a rather large air gap.
>>
>>That would also break the outside magnetic coupling,
>>so basically get you very little core effect.
>>Normally in a potcore with airgap only the inner part is shorter, touches less.
>>?
>>Potcores are nice.
>> https://panteltje.nl/pub/8052AH_BASIC_computer/8052AH_BASIC_computer_inside_img_1727.jpg
>> eighties... EPROM programming voltage generator...
>> https://panteltje.nl/pub/8052AH_BASIC_computer/dc_dc_converter_detail/5V_to_30V_converter.jpg
>>almost a sinewave, no switcher noise...
>
>That last one has a base bias scheme that is more subtle than it
>looks.

Yes, auto-bias!

>I did the same thing, but with the feedback winding in the emitter,
>for a gadget used on the C5A transport.

I have used that circuit with base feedback many many times, even to power an industrial optical link module once.
That old thing from the eighties still works (tested last year)!
Was part of my home control system... programmed in 8052AH BASIC.