bitrex <bitrex@de.lete.earthlink.net> Wrote in message:
> piglet <erichpwagner@hotmail.com> Wrote in message:
>> On 25/01/2016 17:04, bitrex wrote:
>>>
>>> Forgive me, my power supply topology-fu is a little rusty. Still
>>> mucking around with my junk box flash capacitor charger.
>>>
>>> So if I have a surplus tranny with a 1:12 step up ratio that I'm
>>> feeding through a cap with a 10 volt P2P square wave with a +5
>>> volt DC offset, that gives me +5/-5 into the tranny. 1:12 step up
>>> ratio plus bridge voltage doubler gives me about 120 volts out if
>>> I'm not wrong, which is what I'm seeing on the flash
>>> cap.
>>>
>>> I'd like double that. The "secondary" of the tranny (hv side) has
>>> a center tap. Is there a mod I can make which will give me ~250
>>> without radically altering the topology?
>>>
>>
>> How about a bridge tied load to double the primary drive - you use
>> another amplifier driving the other side of the transformer (that is at
>> present grounded) with the anti-phase signal, or is that too radical?
>>
>> piglet
>>
>>
>
> Not too radical, I like it. I think I have room to squeeze another
> '386 on the board.
>
> Not like I don't have enough of them. They're useful for stuff
> other than audio (like driving servos, and this thing here) have
> decent GBW, and cost pennies. Less than some electrolytic
> capacitors for a multi stage CW, even.
>
> --
Tayda Electronics has ~100k LM386Ls in DIP-8 for 23 cents each in
singles.
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Reply by bitrex●January 26, 20162016-01-26
piglet <erichpwagner@hotmail.com> Wrote in message:
> On 25/01/2016 17:04, bitrex wrote:
>>
>> Forgive me, my power supply topology-fu is a little rusty. Still
>> mucking around with my junk box flash capacitor charger.
>>
>> So if I have a surplus tranny with a 1:12 step up ratio that I'm
>> feeding through a cap with a 10 volt P2P square wave with a +5
>> volt DC offset, that gives me +5/-5 into the tranny. 1:12 step up
>> ratio plus bridge voltage doubler gives me about 120 volts out if
>> I'm not wrong, which is what I'm seeing on the flash
>> cap.
>>
>> I'd like double that. The "secondary" of the tranny (hv side) has
>> a center tap. Is there a mod I can make which will give me ~250
>> without radically altering the topology?
>>
>
> How about a bridge tied load to double the primary drive - you use
> another amplifier driving the other side of the transformer (that is at
> present grounded) with the anti-phase signal, or is that too radical?
>
> piglet
>
>
Not too radical, I like it. I think I have room to squeeze another
'386 on the board.
Not like I don't have enough of them. They're useful for stuff
other than audio (like driving servos, and this thing here) have
decent GBW, and cost pennies. Less than some electrolytic
capacitors for a multi stage CW, even.
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Reply by piglet●January 26, 20162016-01-26
On 25/01/2016 17:04, bitrex wrote:
>
> Forgive me, my power supply topology-fu is a little rusty. Still
> mucking around with my junk box flash capacitor charger.
>
> So if I have a surplus tranny with a 1:12 step up ratio that I'm
> feeding through a cap with a 10 volt P2P square wave with a +5
> volt DC offset, that gives me +5/-5 into the tranny. 1:12 step up
> ratio plus bridge voltage doubler gives me about 120 volts out if
> I'm not wrong, which is what I'm seeing on the flash
> cap.
>
> I'd like double that. The "secondary" of the tranny (hv side) has
> a center tap. Is there a mod I can make which will give me ~250
> without radically altering the topology?
>
How about a bridge tied load to double the primary drive - you use
another amplifier driving the other side of the transformer (that is at
present grounded) with the anti-phase signal, or is that too radical?
piglet
Reply by ●January 26, 20162016-01-26
On Tuesday, 26 January 2016 18:07:01 UTC, bitrex wrote:
> tabbypurr Wrote in message:
> > On Tuesday, 26 January 2016 15:10:55 UTC, bitrex wrote:
> >> tabbypurr Wrote in message:
> >> > On Monday, 25 January 2016 20:22:13 UTC, bitrex wrote:
> >
> >> >> Just a quick sketch:
> >> >>
> >> >> https://www.dropbox.com/s/8095sg6mhswyae1/20160125_150825.jpg?dl=0
> >> >
> >> > I guess you'll need to go cockroft-walton.
> >
> >> So if I use the bridge rectifier as part of a two stage CW, in
> >> addition to the center tap, that should give me 2x peak to peak,
> >> rather than 2x peak, right?
> >>
> >> That should work...
> >
> > too vague. But as said, you'll not get close to the theoretical V_out with a C-W.
> Even if it's not continuously loaded?
Offload V_out should climb to theoretical. But give it any load & it nosedives. I'm just saying that expecting more V_out is a common error.
NT
Reply by bitrex●January 26, 20162016-01-26
tabbypurr@gmail.com Wrote in message:
> On Tuesday, 26 January 2016 15:10:55 UTC, bitrex wrote:
>> tabbypurr Wrote in message:
>> > On Monday, 25 January 2016 20:22:13 UTC, bitrex wrote:
>
>> >> Just a quick sketch:
>> >>
>> >> https://www.dropbox.com/s/8095sg6mhswyae1/20160125_150825.jpg?dl=0
>> >
>> > I guess you'll need to go cockroft-walton.
>
>> So if I use the bridge rectifier as part of a two stage CW, in
>> addition to the center tap, that should give me 2x peak to peak,
>> rather than 2x peak, right?
>>
>> That should work...
>
> too vague. But as said, you'll not get close to the theoretical V_out with a C-W.
>
>
> NT
>
> So if I use the bridge rectifier as part of a two stage CW, in
> addition to the center tap, that should give me 2x peak to peak,
> rather than 2x peak, right?
>
> That should work...
too vague. But as said, you'll not get close to the theoretical V_out with a C-W.
NT
Reply by bitrex●January 26, 20162016-01-26
tabbypurr@gmail.com Wrote in message:
> On Monday, 25 January 2016 20:22:13 UTC, bitrex wrote:
>> tabbypurr Wrote in message:
>> > On Monday, 25 January 2016 17:25:53 UTC, bitrex wrote:
>> >> Tim Wescott <tim@seemywebsite.com> Wrote in message:
>> >> > On Mon, 25 Jan 2016 12:04:33 -0500, bitrex wrote:
>
>> >> >> Forgive me, my power supply topology-fu is a little rusty. Still
>> >> >> mucking around with my junk box flash capacitor charger.
>> >> >>
>> >> >> So if I have a surplus tranny with a 1:12 step up ratio that I'm
>> >> >> feeding through a cap with a 10 volt P2P square wave with a +5 volt DC
>> >> >> offset, that gives me +5/-5 into the tranny. 1:12 step up ratio plus
>> >> >> bridge voltage doubler gives me about 120 volts out if I'm not wrong,
>> >> >> which is what I'm seeing on the flash cap.
>> >> >>
>> >> >> I'd like double that. The "secondary" of the tranny (hv side) has
>> >> >> a center tap. Is there a mod I can make which will give me ~250 without
>> >> >> radically altering the topology?
>> >> >
>> >> > You could use a doubler on the secondary side -- but photoflash has been
>> >> > done with flyback converters for decades. Why not use what's tried and
>> >> > true?
>> >
>> >> Already is a doubler there. +5/-5 -> 1:12 -> �2 = ~120?
>> >
>> > so show us the circuit, there may well be an easy fix but no sense suggesting until we know what you've got.
>> >
>> >> And I just wanted to throw this together using some stuff I had in
>> >> the junk box. Makes for a fun exercise as well, I
>> >> guess.
>> >>
>> >> It's just a LM386 "power" amp feeding a surplus audio impedance
>> >> matching transformer "backwards" through a
>> >> capacitor. They seem
>> >> to have a decent amount of bandwidth even up at 20kHz.
>> >
>> > 386s still work at 1MHz. Little interstage audio transformers are well out of their depth at 20kHz.
>
>> Just a quick sketch:
>>
>> https://www.dropbox.com/s/8095sg6mhswyae1/20160125_150825.jpg?dl=0
>
> I guess you'll need to go cockroft-walton.
>
>
> NT
>
So if I use the bridge rectifier as part of a two stage CW, in
addition to the center tap, that should give me 2x peak to peak,
rather than 2x peak, right?
That should work...
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Reply by ●January 25, 20162016-01-25
On Monday, 25 January 2016 23:18:31 UTC, tabbypurr wrote:
> I guess you'll need to go cockroft-walton.
Just bear in mind their V_out is normally woefully short of the ideal.
NT
Reply by ●January 25, 20162016-01-25
On Monday, 25 January 2016 20:22:13 UTC, bitrex wrote:
> tabbypurr Wrote in message:
> > On Monday, 25 January 2016 17:25:53 UTC, bitrex wrote:
> >> Tim Wescott <tim@seemywebsite.com> Wrote in message:
> >> > On Mon, 25 Jan 2016 12:04:33 -0500, bitrex wrote:
> >> >> Forgive me, my power supply topology-fu is a little rusty. Still
> >> >> mucking around with my junk box flash capacitor charger.
> >> >>
> >> >> So if I have a surplus tranny with a 1:12 step up ratio that I'm
> >> >> feeding through a cap with a 10 volt P2P square wave with a +5 volt DC
> >> >> offset, that gives me +5/-5 into the tranny. 1:12 step up ratio plus
> >> >> bridge voltage doubler gives me about 120 volts out if I'm not wrong,
> >> >> which is what I'm seeing on the flash cap.
> >> >>
> >> >> I'd like double that. The "secondary" of the tranny (hv side) has
> >> >> a center tap. Is there a mod I can make which will give me ~250 without
> >> >> radically altering the topology?
> >> >
> >> > You could use a doubler on the secondary side -- but photoflash has been
> >> > done with flyback converters for decades. Why not use what's tried and
> >> > true?
> >
> >> Already is a doubler there. +5/-5 -> 1:12 -> �2 = ~120?
> >
> > so show us the circuit, there may well be an easy fix but no sense suggesting until we know what you've got.
> >
> >> And I just wanted to throw this together using some stuff I had in
> >> the junk box. Makes for a fun exercise as well, I
> >> guess.
> >>
> >> It's just a LM386 "power" amp feeding a surplus audio impedance
> >> matching transformer "backwards" through a
> >> capacitor. They seem
> >> to have a decent amount of bandwidth even up at 20kHz.
> >
> > 386s still work at 1MHz. Little interstage audio transformers are well out of their depth at 20kHz.
> On Monday, 25 January 2016 17:25:53 UTC, bitrex wrote:
>> Tim Wescott <tim@seemywebsite.com> Wrote in message:
>> > On Mon, 25 Jan 2016 12:04:33 -0500, bitrex wrote:
>> >
>> >> Forgive me, my power supply topology-fu is a little rusty. Still
>> >> mucking around with my junk box flash capacitor charger.
>> >>
>> >> So if I have a surplus tranny with a 1:12 step up ratio that I'm
>> >> feeding through a cap with a 10 volt P2P square wave with a +5 volt DC
>> >> offset, that gives me +5/-5 into the tranny. 1:12 step up ratio plus
>> >> bridge voltage doubler gives me about 120 volts out if I'm not wrong,
>> >> which is what I'm seeing on the flash cap.
>> >>
>> >> I'd like double that. The "secondary" of the tranny (hv side) has
>> >> a center tap. Is there a mod I can make which will give me ~250 without
>> >> radically altering the topology?
>> >
>> > You could use a doubler on the secondary side -- but photoflash has been
>> > done with flyback converters for decades. Why not use what's tried and
>> > true?
>
>> Already is a doubler there. +5/-5 -> 1:12 -> �2 = ~120?
>
> so show us the circuit, there may well be an easy fix but no sense suggesting until we know what you've got.
>
>> And I just wanted to throw this together using some stuff I had in
>> the junk box. Makes for a fun exercise as well, I
>> guess.
>>
>> It's just a LM386 "power" amp feeding a surplus audio impedance
>> matching transformer "backwards" through a
>> capacitor. They seem
>> to have a decent amount of bandwidth even up at 20kHz.
>
> 386s still work at 1MHz. Little interstage audio transformers are well out of their depth at 20kHz.
>
>
> NT
>