Reply by bitrex January 26, 20162016-01-26
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. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
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. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
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 >
Even if it's not continuously loaded? -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
Reply by January 26, 20162016-01-26
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
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 -> &#2013265943;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... -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
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 -> &#2013265943;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
Reply by bitrex January 25, 20162016-01-25
tabbypurr@gmail.com 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 -> &#2013265943;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 >
Just a quick sketch: https://www.dropbox.com/s/8095sg6mhswyae1/20160125_150825.jpg?dl=0 -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/