On Thursday, 25 August 2016 14:30:43 UTC+1, dagmarg...@yahoo.com wrote:
> Still, for $1 at the thrift store he gets a good switch, pre-fab
> magnetics, and a PWM chip if he wants it. That's not bad.
I've never seen a PWM chip in a cheapo wallwart. Ever.
NT
Reply by Tim Williams●August 27, 20162016-08-27
"Jasen Betts" <jasen@xnet.co.nz> wrote in message
news:npqstn$4j2$2@gonzo.alcatraz...
>> (Hint: superglue is a key disassembly tool...)
>
> Huh? Superglue for dissasembly - how does that work?
> Some sort of solvent I could understand, but glue?
Think diagonally. ;-) You'll likely break as many cores as not, during
disassembly... the final step of disassembly is partial reassembly. :^)
Super glue is just fine for redoing fractured cores. The fracture is
usually simple and rough, so superglue adds little gap, and the pieces align
accurately. You only need to avoid fractures on super-high mu cores
(>5000?), where even that little gap will spoil the inductivity a bit.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com
Reply by bitrex●August 25, 20162016-08-25
On 08/25/2016 06:49 AM, Winfield Hill wrote:
> Michael A. Terrell wrote...
>>
>> How about a cheap Boost converter module? $12.12 USD
>> DC-DC-12V-24V input to 100V-250V output @ 70W
>> <http://www.ebay.com/itm/131675760033
>
> Too bad those are only available shipped from China.
> That includes the Amazon sellers of this nice item.
>
>
And my junkbox switcher is already up and running! ; )
Reply by ●August 25, 20162016-08-25
On Thursday, August 25, 2016 at 3:38:47 AM UTC-4, tabb...@gmail.com wrote:
> On Thursday, 25 August 2016 03:15:19 UTC+1, dagmarg...@yahoo.com wrote:
> > On Wednesday, August 24, 2016 at 4:35:55 PM UTC-4, tabbypurr wrote:
> > > On Wednesday, 24 August 2016 14:54:45 UTC+1, dagmarg...@yahoo.com wrote:
> > > > > >> "bitrex" wrote ...
> > >
> > > > > >>> I need to throw together a ~150 volt supply at a few 10s
> > > > > >>> of mA to test a circuit idea, but I don't have much in
> > > > > >>> the way of MOSFETs in my junk box to build a switcher from.
> > >
> > > > You could tear up a 12v wallwart smps & run it backwards. That'll
> > > > get you everything you need, parts-wise.
> > >
> > > as long as everything means the transformer.
> >
> > He just needed a switch, hence "everything you need," but this would
> > also get him a flyback transformer, high voltage switch, & a crappy
> > h.v. cap.
>
> It gets him 200v or 400v low beta low current transistors, a reservoir cap that's too small by far, etc.
>
>
> NT
The switches are always MOSFETs these days, IME, all sized for 220VAC
inputs. Haven't seen a BJT ever.
The reservoir cap's value is fine for 10mA, but ESR is poor.
Still, for $1 at the thrift store he gets a good switch, pre-fab
magnetics, and a PWM chip if he wants it. That's not bad.
Cheers,
James Arthur
Reply by Rob●August 25, 20162016-08-25
Winfield Hill <hill@rowland.harvard.edu> wrote:
> Michael A. Terrell wrote...
>>
>> How about a cheap Boost converter module? $12.12 USD
>> DC-DC-12V-24V input to 100V-250V output @ 70W
>> <http://www.ebay.com/itm/131675760033
>
> Too bad those are only available shipped from China.
> That includes the Amazon sellers of this nice item.
China is the main and soon the only source of electronics modules.
Local stocking went out even before local manufacturing, so what
do you expect?
Reply by Winfield Hill●August 25, 20162016-08-25
Michael A. Terrell wrote...
>
> How about a cheap Boost converter module? $12.12 USD
> DC-DC-12V-24V input to 100V-250V output @ 70W
> <http://www.ebay.com/itm/131675760033
Too bad those are only available shipped from China.
That includes the Amazon sellers of this nice item.
--
Thanks,
- Win
Reply by ●August 25, 20162016-08-25
On Thursday, 25 August 2016 03:15:19 UTC+1, dagmarg...@yahoo.com wrote:
> On Wednesday, August 24, 2016 at 4:35:55 PM UTC-4, tabbypurr wrote:
> > On Wednesday, 24 August 2016 14:54:45 UTC+1, dagmarg...@yahoo.com wrote:
> > > > >> "bitrex" wrote ...
> >
> > > > >>> I need to throw together a ~150 volt supply at a few 10s
> > > > >>> of mA to test a circuit idea, but I don't have much in
> > > > >>> the way of MOSFETs in my junk box to build a switcher from.
> >
> > > You could tear up a 12v wallwart smps & run it backwards. That'll
> > > get you everything you need, parts-wise.
> >
> > as long as everything means the transformer.
>
> He just needed a switch, hence "everything you need," but this would
> also get him a flyback transformer, high voltage switch, & a crappy
> h.v. cap.
It gets him 200v or 400v low beta low current transistors, a reservoir cap that's too small by far, etc.
NT
Reply by ●August 24, 20162016-08-24
On Wednesday, August 24, 2016 at 10:15:19 PM UTC-4, dagmarg...@yahoo.com wrote:
> On Wednesday, August 24, 2016 at 4:35:55 PM UTC-4, tabb...@gmail.com wrote:
> > On Wednesday, 24 August 2016 14:54:45 UTC+1, dagmarg...@yahoo.com wrote:
> > > > >> "bitrex" wrote ...
> >
> > > > >>> I need to throw together a ~150 volt supply at a few 10s
> > > > >>> of mA to test a circuit idea, but I don't have much in
> > > > >>> the way of MOSFETs in my junk box to build a switcher from.
> >
> > > You could tear up a 12v wallwart smps & run it backwards. That'll
> > > get you everything you need, parts-wise.
> >
> > as long as everything means the transformer.
> >
> >
> > NT
>
> He just needed a switch, hence "everything you need," but this would
> also get him a flyback transformer, high voltage switch, & a crappy
> h.v. cap.
>
> Cheers,
> James Arthur
Oh, and a PWM controller, too. --ja
Reply by ●August 24, 20162016-08-24
On Wednesday, August 24, 2016 at 4:35:55 PM UTC-4, tabb...@gmail.com wrote:
> On Wednesday, 24 August 2016 14:54:45 UTC+1, dagmarg...@yahoo.com wrote:
> > > >> "bitrex" wrote ...
>
> > > >>> I need to throw together a ~150 volt supply at a few 10s
> > > >>> of mA to test a circuit idea, but I don't have much in
> > > >>> the way of MOSFETs in my junk box to build a switcher from.
>
> > You could tear up a 12v wallwart smps & run it backwards. That'll
> > get you everything you need, parts-wise.
>
> as long as everything means the transformer.
>
>
> NT
He just needed a switch, hence "everything you need," but this would
also get him a flyback transformer, high voltage switch, & a crappy
h.v. cap.
Cheers,
James Arthur
Reply by ●August 24, 20162016-08-24
On Wednesday, 24 August 2016 14:54:45 UTC+1, dagmarg...@yahoo.com wrote:
> > >> "bitrex" wrote ...
> > >>> I need to throw together a ~150 volt supply at a few 10s
> > >>> of mA to test a circuit idea, but I don't have much in
> > >>> the way of MOSFETs in my junk box to build a switcher from.
> You could tear up a 12v wallwart smps & run it backwards. That'll
> get you everything you need, parts-wise.