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Audio transformer as step up transformer

Started by bitrex December 4, 2015
I have a few little PCB mount audio impedance matching
 transformers, the impedance transformation given on the bag is
 500 to 4 ohms.

Would these work OK in reverse to step low voltage up to high
 voltage at a few mA output current and maybe 30 kHz? Efficiency
 not terribly important...

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On a sunny day (Fri, 4 Dec 2015 10:24:32 -0500 (EST)) it happened bitrex
<bitrex@de.lete.earthlink.net> wrote in <%ei8y.18168$2N.6768@fx25.iad>:

> >I have a few little PCB mount audio impedance matching > transformers, the impedance transformation given on the bag is > 500 to 4 ohms. > >Would these work OK in reverse to step low voltage up to high > voltage at a few mA output current and maybe 30 kHz? Efficiency > not terribly important...
Yes I have used some of those small audio transformers for just that. Losses my be higher at 30 kHz though, aouside the band they were designed for.
On Fri, 4 Dec 2015 10:24:32 -0500 (EST), bitrex
<bitrex@de.lete.earthlink.net> wrote:

> >I have a few little PCB mount audio impedance matching > transformers, the impedance transformation given on the bag is > 500 to 4 ohms. > >Would these work OK in reverse to step low voltage up to high > voltage at a few mA output current and maybe 30 kHz? Efficiency > not terribly important...
Sure, as long as you don't break down the insulation. A couple of hundred volts peak should be OK for most audio transformers. The frequency will need to be pretty high, not 60 Hz. Use a Cockroft Walton thing to get higher voltage. https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/Z206.pdf That makes 1200 volts from 5 volts.
On Fri, 04 Dec 2015 10:24:32 -0500, bitrex wrote:

> I have a few little PCB mount audio impedance matching > transformers, the impedance transformation given on the bag is 500 to 4 > ohms. > > Would these work OK in reverse to step low voltage up to high > voltage at a few mA output current and maybe 30 kHz? Efficiency not > terribly important...
Why use an audio transformer when there's purpose-built ones out there to buy? http://www.digikey.com/product-search/en?keywords=750811445 -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
On a sunny day (Fri, 04 Dec 2015 16:23:25 GMT) it happened Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote in <n3selt$4kt$1@news.datemas.de>:

>On a sunny day (Fri, 4 Dec 2015 10:24:32 -0500 (EST)) it happened bitrex ><bitrex@de.lete.earthlink.net> wrote in <%ei8y.18168$2N.6768@fx25.iad>: > >> >>I have a few little PCB mount audio impedance matching >> transformers, the impedance transformation given on the bag is >> 500 to 4 ohms. >> >>Would these work OK in reverse to step low voltage up to high >> voltage at a few mA output current and maybe 30 kHz? Efficiency >> not terribly important... > >Yes > >I have used some of those small audio transformers for just that. >Losses my be higher at 30 kHz though, aouside the band they were designed for.
PS http://panteltje.com/panteltje/pic/gm_pic2/ in 3.8 V out 400 V 1:10, flyback pulse used, watch polarity, That is a conrad.nl audio transformer. Of course you have to watch for high voltage breakdown. And watch your PWM pulse width. and and and works 24/7 now for a year or so..
Tim Wescott <seemywebsite@myfooter.really> Wrote in message:
> On Fri, 04 Dec 2015 10:24:32 -0500, bitrex wrote: > >> I have a few little PCB mount audio impedance matching >> transformers, the impedance transformation given on the bag is 500 to 4 >> ohms. >> >> Would these work OK in reverse to step low voltage up to high >> voltage at a few mA output current and maybe 30 kHz? Efficiency not >> terribly important... > > Why use an audio transformer when there's purpose-built ones out there to > buy? > > http://www.digikey.com/product-search/en?keywords=750811445 > > -- > > Tim Wescott > Wescott Design Services > http://www.wescottdesign.com >
I obtained a bunch of them at a very reasonable price: $0 If it's fo' free, it's fo' me. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
>I have a few little PCB mount audio impedance matching > transformers, the impedance transformation given on the bag is > 500 to 4 ohms. > >Would these work OK in reverse to step low voltage up to high > voltage at a few mA output current and maybe 30 kHz? Efficiency > not terribly important...
I've seen that done before, stepping up a battery-powered oscillator's output to a higher voltage which is then rectified and filtered. It worked well enough to run a bunch of NE-2 neon lights.
On Sat, 05 Dec 2015 01:24:32 +1000, bitrex <bitrex@de.lete.earthlink.net>  
wrote:

> > I have a few little PCB mount audio impedance matching > transformers, the impedance transformation given on the bag is > 500 to 4 ohms. > > Would these work OK in reverse to step low voltage up to high > voltage at a few mA output current and maybe 30 kHz? Efficiency > not terribly important... >
If these are the little ones that used to be common on old, cheap transistor radios (size about .5 inch cubed) then the bandwidth is about 300 - 3k. I once put one on an N and D set and tested it. Performance outside than bandwidth dropped extremely fast.
On Fri, 04 Dec 2015 14:41:09 -0500, bitrex wrote:

> Tim Wescott <seemywebsite@myfooter.really> Wrote in message: >> On Fri, 04 Dec 2015 10:24:32 -0500, bitrex wrote: >> >>> I have a few little PCB mount audio impedance matching >>> transformers, the impedance transformation given on the bag is 500 to >>> 4 ohms. >>> >>> Would these work OK in reverse to step low voltage up to high >>> voltage at a few mA output current and maybe 30 kHz? Efficiency not >>> terribly important... >> >> Why use an audio transformer when there's purpose-built ones out there >> to buy? >> >> http://www.digikey.com/product-search/en?keywords=750811445 >> >> -- >> >> Tim Wescott Wescott Design Services http://www.wescottdesign.com >> >> > I obtained a bunch of them at a very reasonable price: $0 > > If it's fo' free, it's fo' me.
Good reason! -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
"David Eather" <eather@tpg.com.au> Wrote in message:
> On Sat, 05 Dec 2015 01:24:32 +1000, bitrex <bitrex@de.lete.earthlink.net> > wrote: > >> >> I have a few little PCB mount audio impedance matching >> transformers, the impedance transformation given on the bag is >> 500 to 4 ohms. >> >> Would these work OK in reverse to step low voltage up to high >> voltage at a few mA output current and maybe 30 kHz? Efficiency >> not terribly important... >> > > If these are the little ones that used to be common on old, cheap > transistor radios (size about .5 inch cubed) then the bandwidth is about > 300 - 3k. I once put one on an N and D set and tested it. Performance > outside than bandwidth dropped extremely fast. >
I'll post a picture later, that seems about right. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/