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Bridge rectifier question

Started by bitrex January 25, 2016
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?

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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? -- www.wescottdesign.com
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? > > -- > www.wescottdesign.com >
Already is a doubler there. +5/-5 -> 1:12 -> &times;2 = ~120? 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. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
On Mon, 25 Jan 2016 12:25:14 -0500, 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? >> >> -- >> www.wescottdesign.com >> >> > Already is a doubler there. +5/-5 -> 1:12 -> &Atilde;&mdash;2 = ~120? > > 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 acapacitor. They seem to have > a decent amount of bandwidth even up at 20kHz.
Google "Cockcroft-Walton". I'm probably over-summarizing, but the C-W recognizes that there's no reason to stop at doubling if you have enough capacitors and diodes. I've never built one, but a few people on the group deal with toobs (photomultiplier?) that need low-current HV supplies, and know about them. -- www.wescottdesign.com
Tim Wescott <tim@seemywebsite.com> Wrote in message:
> On Mon, 25 Jan 2016 12:25:14 -0500, 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? >>> >>> -- >>> www.wescottdesign.com >>> >>> >> Already is a doubler there. +5/-5 -> 1:12 -> &times;2 = ~120? >> >> 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 acapacitor. They seem to have >> a decent amount of bandwidth even up at 20kHz. > > Google "Cockcroft-Walton". I'm probably over-summarizing, but the C-W > recognizes that there's no reason to stop at doubling if you have enough > capacitors and diodes. > > I've never built one, but a few people on the group deal with toobs > (photomultiplier?) that need low-current HV supplies, and know about them. > > -- > www.wescottdesign.com >
Indeed, I've seen the CW. I'm just wondering if there's a hack I can apply to push it up another factor of 2 with what I've already got without too many modifications to the toplogy, as...um...I did the math wrong when designing it and already have shit soldered to the board... -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
On 25.1.16 19:34, bitrex wrote:
> Tim Wescott <tim@seemywebsite.com> Wrote in message: >> On Mon, 25 Jan 2016 12:25:14 -0500, 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? >>>> >>>> -- >>>> www.wescottdesign.com >>>> >>>> >>> Already is a doubler there. +5/-5 -> 1:12 -> &times;2 = ~120? >>> >>> 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 acapacitor. They seem to have >>> a decent amount of bandwidth even up at 20kHz. >> >> Google "Cockcroft-Walton". I'm probably over-summarizing, but the C-W >> recognizes that there's no reason to stop at doubling if you have enough >> capacitors and diodes. >> >> I've never built one, but a few people on the group deal with toobs >> (photomultiplier?) that need low-current HV supplies, and know about them. >> >> -- >> www.wescottdesign.com >> > > Indeed, I've seen the CW. I'm just wondering if there's a hack I > can apply to push it up another factor of 2 with what I've > already got without too many modifications to the toplogy, > as...um...I did the math wrong when designing it and already have > shit soldered to the board... >
Sorry, there is no simple way. At least, you need more capacitors and diodes, and it leads to the CW ladder. -- -TV
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
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 -> &times;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/
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
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