Make 2000V at 100uA

[Tim Wescott]

Or more (volts that is).

Any quick & dirty circuits that'll do this? Something that self-limits
in current would be nice, but not necessary. I want to test voltage
regulators. Ideally it'd be battery powered, but that's not a necessity.

Just looking for a quickie one-off.

Thanks.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

[John Larkin]

On Sun, 19 Mar 2017 19:14:36 -0500, Tim Wescott
<seemyw...@myfooter.really> wrote:

>Or more (volts that is).
>
>Any quick & dirty circuits that'll do this? Something that self-limits
>in current would be nice, but not necessary. I want to test voltage
>regulators. Ideally it'd be battery powered, but that's not a necessity.
>
>Just looking for a quickie one-off.
>
>Thanks.

Ebay copier high voltage supply?

Or but a used HV bench supply, which is handy to have around.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

[Winfield Hill]

John Larkin wrote...
>
> Tim Wescott wrote:
>> Any quick & dirty circuits that'll do this? ...

>> I want to test voltage regulators.
>>

>> Just looking for a quickie one-off.
>

> Ebay copier high voltage supply? Or a used

> HV bench supply, which is handy to have around.

What, you didn't suggest your Cockcroft-Walton
HV multiplier circuit and parts? With higher
starting supply voltages it can easily do 2kV.


--
Thanks,
- Win

[bill....@ieee.org]

I posted one here in 2013.

It shows up - well down the page - here

http://sophia-electronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm

The difficult bit is getting a decent oscillation frequency despite the relatively high interwinding capacitances you get in high turns-ratio transformers. Banked winding help, but it's hard to find multi-section formers these days.

--
Bill Sloman, Sydney

[Cursitor Doom]

On Sun, 19 Mar 2017 18:01:19 -0700, Winfield Hill wrote:

> What, you didn't suggest your Cockcroft-Walton HV multiplier circuit
> and parts? With higher starting supply voltages it can easily do 2kV.

Yes, and automatically self-limiting current - after a fashion - as the
chain grows.

[bitrex]

On 03/19/2017 08:14 PM, Tim Wescott wrote:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>
> Thanks.
>

This is pretty quick and dirty way to get ~1kV, could probably be
adapted for 2:

http://imgur.com/a/ntUFx

Hope I got the dots right...

[Robert Baer]

Tim Wescott wrote:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>
> Thanks.
>

Steal the xfmr, cap and diode from a microwave oven; the maggie seems
to get a regulated drive (but it also is the second diode in the DC
scheme of things).
Or, a flyback xfmr in a joule thief configuration?


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[mike]

On 3/19/2017 5:14 PM, Tim Wescott wrote:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>
> Thanks.
>

How much voltage can you get out of a laptop backlight supply?

[John Larkin]

On 19 Mar 2017 18:01:19 -0700, Winfield Hill

If you only need one of something, it's a lot easier to buy than
build. Less fun, of course.

[whit3rd]

On Sunday, March 19, 2017 at 9:47:55 PM UTC-7, mike wrote:
> On 3/19/2017 5:14 PM, Tim Wescott wrote:
> > Or more (volts that is).

> How much voltage can you get out of a laptop backlight supply?

Probably, enough. eBay search for "CCFL transformer" pulls up some of the
HV magnetics parts, but also complete DC/DC converters, for not much money.

[pcdh...@gmail.com]

>If you only need one of something, it's a lot easier to buy than
>build. Less fun, of course.

I'm a fan of the HP 6110A. It's 0-3 kV, 6 mA, with thumbwheel switches to set the voltage.

Just the ticket for PMTs and such stuff.

Cheers

Phil Hobbs

[George Herold]

That was my thought C-W from 120 or 240 AC?
(Or do you need a faster frequency?)
Not sure it would be dirty or quick though.

George H.
>
>
> --
> Thanks,
> - Win

[dagmarg...@yahoo.com]

On Sunday, March 19, 2017 at 8:14:44 PM UTC-4, Tim Wescott wrote:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>
> Thanks.

For a simple start, see LTC AN29 Fig. 49.
http://www.linear.com/docs/4122

The flyback transformer has been discontinued; I'd suggest adapting the
circuit for the Pulse PA-0367A (1:12 transformer) instead.

The Wurth 750 032 050 (1:10) is available from Mouser, too.

Another approach is to use one of the multi-winding inductors, like
this:
http://www.edn.com/design/power-management/4334168/1-kV-power-supply-produces-a-continuous-arc

Cheers,
James Arthur

[John Larkin]

I have a nice Kepco 3KV supply. It has a kilovolt-step rotary switch
and a 10-turn pot. There is one tube inside.

We also have a rackmount beast Bertan 10KV supply, which is rarely
used. It is sometimes useful, like to see where a transformer or
connector or PCB actually breaks down.

I was doing a breakdown test on a PCB and kept getting weird currents.
It was corona on the test leads.

[John Larkin]

On Mon, 20 Mar 2017 06:18:37 -0700 (PDT), George Herold
<ghe...@teachspin.com> wrote:

>On Sunday, March 19, 2017 at 9:01:33 PM UTC-4, Winfield Hill wrote:
>> John Larkin wrote...
>> >
>> > Tim Wescott wrote:
>> >> Any quick & dirty circuits that'll do this? ...
>> >> I want to test voltage regulators.
>> >>
>> >> Just looking for a quickie one-off.
>> >
>> > Ebay copier high voltage supply? Or a used
>> > HV bench supply, which is handy to have around.
>>
>> What, you didn't suggest your Cockcroft-Walton
>> HV multiplier circuit and parts? With higher
>> starting supply voltages it can easily do 2kV.

OK, OK, here it is.

https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/T840_PS.pdf

The transformer is 1:1, not much step-up, but the cute little MMBD5004
diodes (and PCB clearances) couldn't handle much more.

The PCB layout was a real challenge, maintaining the surface and
internal voltage clearances without making it too ugly.

https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/T840_PCB_13.jpg

https://dl.dropboxusercontent.com/u/53724080/PCBs/T840_E1.jpg

https://dl.dropboxusercontent.com/u/53724080/PCBs/Rounded_HV_Pads.jpg

Here's a little one, 5-to-1200 volts as I recall. Hand-wound pot core
step-up.

https://dl.dropboxusercontent.com/u/53724080/PCBs/Z206_pcb.JPG

>
>That was my thought C-W from 120 or 240 AC?
>(Or do you need a faster frequency?)
>Not sure it would be dirty or quick though.

60 Hz c-w would need big caps, and they might store a dangerous amount
of energy.

[George Herold]

Right. (I'm scared of HV.) Could you make a C-W with just a function generator?
~10Vp-p at ~200mA (lots of stages...) Maybe a little transformer before the C-W?

That would be quick and dirty. (If you had the transformer.)

George H.

[mike]

It's not exactly "battery powered", but a TEK 576 curve tracer will put
out 1500V. Doesn't everybody have one of those somewhere in the lab?

[Tim Wescott]

On Sun, 19 Mar 2017 20:19:09 -0800, Robert Baer wrote:

> Tim Wescott wrote:
>> Or more (volts that is).
>>
>> Any quick & dirty circuits that'll do this? Something that self-limits
>> in current would be nice, but not necessary. I want to test voltage
>> regulators. Ideally it'd be battery powered, but that's not a
>> necessity.
>>
>> Just looking for a quickie one-off.
>>
>> Thanks.
>>
> Steal the xfmr, cap and diode from a microwave oven; the maggie seems
> to get a regulated drive (but it also is the second diode in the DC
> scheme of things).
> Or, a flyback xfmr in a joule thief configuration?

I like the idea of something that's inherently low current. 500mA at
2000V seems a lot scarier than 100uA at same.

[bitrex]

What about this class C thing, it goes to ~1kV using a single BJT. Add a
few multiplier stages for 2, should put out 100uA no problem.

OP could wind the xfmr by hand on a small ferrite toroid.

The BJT should probably be at least a 150V 3 amp type. Tank freq is
around 100kHz

Version 4
SHEET 1 1380 680
WIRE 64 32 -80 32
WIRE 208 32 208 -16
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WIRE 480 64 304 64
WIRE 656 64 544 64
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WIRE 992 64 912 64
WIRE 1152 64 1056 64
WIRE 1360 64 1152 64
WIRE 208 112 208 32
WIRE 304 112 304 64
WIRE -272 128 -272 96
WIRE -80 128 -80 32
WIRE 64 128 64 32
WIRE 656 128 656 64
WIRE 912 128 912 64
WIRE 1152 128 1152 64
WIRE 1360 128 1360 64
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WIRE 752 240 656 240
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WIRE 1152 240 1152 192
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WIRE 144 416 96 416
WIRE -80 480 -80 416
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WIRE -80 640 -80 544
WIRE 400 640 400 368
WIRE 400 640 -80 640
FLAG 208 -16 Vcc
FLAG 208 560 0
FLAG 464 336 0
FLAG -272 240 0
FLAG -272 96 Vcc
FLAG 1360 336 0
FLAG 656 384 HV_OUT
IOPIN 656 384 Out
SYMBOL ind2 192 96 R0
WINDOW 3 34 74 Left 2
SYMATTR Value 47ṁH
SYMATTR InstName L1
SYMBOL ind2 288 96 R0
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SYMBOL ind2 336 384 R180
WINDOW 0 36 80 Left 2
WINDOW 3 36 40 Left 2
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SYMBOL cap 816 224 R90
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WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
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SYMATTR Value 2.2ṁF
SYMBOL diode 928 192 R180
WINDOW 0 24 64 Left 2
WINDOW 3 52 27 Left 2
SYMATTR InstName D2
SYMATTR Value RFN1L7S
SYMBOL diode 1136 128 R0
WINDOW 3 -118 31 Left 2
SYMATTR Value RFN1L7S
SYMATTR InstName D3
SYMBOL diode 1376 192 R180
WINDOW 0 24 64 Left 2
WINDOW 3 58 33 Left 2
SYMATTR InstName D4
SYMATTR Value RFN1L7S
TEXT -392 344 Left 2 !K1 L1 L2 L3 1
TEXT -392 296 Left 2 !.tran 1 startup uic

[bitrex]

Might need a catch diode on the base to avoid blowing the e-b junction too

[bitrex]

For 100uA 1uF at 600V should be plenty. Just like what they might use
for a small electrostatic CRT acceleration voltage.

Probably not fun if you touched them but doesn't sound super-dangerous.

It's possible to step up an AC RMS voltage around 1 order of magnitude
with 5 stages, and neglecting diode losses and using 1uF caps @ 60 Hz
with a 100uA load I calculate a loaded drop of around 100 volts - no biggie.

[bitrex]

Use the "boosting transformer" config I posted earlier and you could do
it in 4 stages probably

[olds...@tubes.com]

On Sun, 19 Mar 2017 19:14:36 -0500, Tim Wescott
<seemyw...@myfooter.really> wrote:

>Or more (volts that is).
>
>Any quick & dirty circuits that'll do this? Something that self-limits
>in current would be nice, but not necessary. I want to test voltage
>regulators. Ideally it'd be battery powered, but that's not a necessity.
>
>Just looking for a quickie one-off.
>
>Thanks.

Find yourself a used electric fence charger on ebay or elsewhere. They
output around 5000v, (or less) but are safe as far as the current. THere
are two kinds. One is a pulser. It puts out pulses of voltage about once
per second. The other is a steady voltage (often called a "weed
burner"). note: some of the pulse ones are called "weed burners" too.

You probably want the steady voltage type.

* Since you may not know about these things, they are connected to a
bare electric wire that surrounds livestock. Animals quickly learn that
touching that wire gives them an unpleasant shock, so they stay away.
Weeds often grow and touch these wires, and too many can drain the
voltage so it no longer is effective with the animals. The "weed burner"
ones are intended to burn the weeds away, where they contact the fence
wires.

[bitrex]

On 03/20/2017 01:26 PM, Tim Wescott wrote:
> On Sun, 19 Mar 2017 20:19:09 -0800, Robert Baer wrote:
>
>> Tim Wescott wrote:
>>> Or more (volts that is).
>>>
>>> Any quick & dirty circuits that'll do this? Something that self-limits
>>> in current would be nice, but not necessary. I want to test voltage
>>> regulators. Ideally it'd be battery powered, but that's not a
>>> necessity.
>>>
>>> Just looking for a quickie one-off.
>>>
>>> Thanks.
>>>
>> Steal the xfmr, cap and diode from a microwave oven; the maggie seems
>> to get a regulated drive (but it also is the second diode in the DC
>> scheme of things).
>> Or, a flyback xfmr in a joule thief configuration?
>
> I like the idea of something that's inherently low current. 500mA at
> 2000V seems a lot scarier than 100uA at same.
>

Sure, if you decide to go the C-W route just do the calculations to use
caps just large enough to provide the required 100uA output current
without too severe a voltage drop, and if anything that draws more than
a couple mA gets connected (ur hand) the calcs say that the output ends
up crowbarred down into the dirt.

Don't taze me, bro!

[bitrex]

On 03/20/2017 03:02 PM, olds...@tubes.com wrote:

> * Since you may not know about these things, they are connected to a
> bare electric wire that surrounds livestock. Animals quickly learn that
> touching that wire gives them an unpleasant shock, so they stay away.
> Weeds often grow and touch these wires, and too many can drain the
> voltage so it no longer is effective with the animals. The "weed burner"
> ones are intended to burn the weeds away, where they contact the fence
> wires.

I'm not sure why I'd buy a product _designed_ to set my property on fire...

[Jasen Betts]

On 2017-03-20, Tim Wescott <seemyw...@myfooter.really> wrote:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>
> Thanks.

These are pretty impressive, I can beleive they have 2W (or greater) output, the
spark very loud I have not tried to measure the voltage

the output is strong strong enough to cause visible damage to static shielding bags

https://www.aliexpress.com/wholesale?catId=0&SearchText=400kv



--
This email has not been checked by half-arsed antivirus software

[mike]

$10 on EBAY will get you a stun gun.
Point being that the high voltage stuff is done. All you'd need to do is
design in some regulation. Diode, cap, adjustable spark gap shunt
regulator.

[Lasse Langwadt Christensen]

Den mandag den 20. marts 2017 kl. 01.14.44 UTC+1 skrev Tim Wescott:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>

a few of these, or mayby just a more multiplier stages

http://www.ebay.com/itm/272192879496

[Tim Wescott]

So, does a $10 stun gun from eBay generate 2000V unloaded?

[Tim Wescott]

I grew up in an area rural enough to have caught one of these in my back
ducking under a fence. Very impressive.

I guess my dad got to watch while my grandfather peed on one -- he claims
he saw it coming but not soon enough to say anything. He also reports
thinking it was hilarious, so I'm not so sure about the first claim.

[whit3rd]

On Monday, March 20, 2017 at 9:50:22 AM UTC-7, George Herold wrote:
> On Monday, March 20, 2017 at 12:31:58 PM UTC-4, John Larkin wrote:

> > 60 Hz c-w would need big caps, and they might store a dangerous amount
> > of energy.
>
> Right. (I'm scared of HV.) Could you make a C-W with just a function generator?
> ~10Vp-p at ~200mA (lots of stages...) Maybe a little transformer before the C-W?

For 2000V at 100 uA, i.e. a quarter watt, that might actually work. Triangle
wave for lowest output ripple, and a CCFL transformer for high ratio boost,
you might only need a couple of CW stages. For low ripple, though, it
has to be FULLWAVE C-W, so it's four diodes per stage instead of two.

[George Herold]

Right, at first blush the numbers seem to work. I could use a
~2kV/ 100uA power supply, that worked off my function generator.
(I wouldn't want to blow out my FG though.. transformer on the
output... (I could start with more R and 10uA.)
I've not done a lot of transformers, a pot core is easy.

Can't I do fullwave with a FG? (I've only made a C-W once, on my
bench... with a function generator.)
And I have no idea about the triangle wave, (well only a small
idea about current into a cap), but that all makes it more fun!

George H.

[mike]

On 3/20/2017 3:17 PM, Tim Wescott wrote:

>>> Don't taze me, bro!
>> $10 on EBAY will get you a stun gun.
>> Point being that the high voltage stuff is done. All you'd need to do
>> is design in some regulation. Diode, cap, adjustable spark gap shunt
>> regulator.
>
> So, does a $10 stun gun from eBay generate 2000V unloaded?
>

I expect so. It's rated at 60,000V. For twice the price
you can get one advertised as 500MV. ;-)
If you can get an arc between the terminals, it's gotta be
better than 2KV.
IIRC it's 1KV/mm give or take an order of magnitude.
I think I'd worry more about getting the voltage down to 2KV.

Point is...the transformer you'd want is probably in there.
Motorcycle spark coil would also work.

[whit3rd]

On Monday, March 20, 2017 at 5:35:17 PM UTC-7, George Herold wrote:
> On Monday, March 20, 2017 at 7:11:01 PM UTC-4, whit3rd wrote:
> > On Monday, March 20, 2017 at 9:50:22 AM UTC-7, George Herold wrote:
> > > On Monday, March 20, 2017 at 12:31:58 PM UTC-4, John Larkin wrote:
> >

> > > > 60 Hz c-w would need big caps...

> > > Right. (I'm scared of HV.) Could you make a C-W with just a function generator?
> > > ~10Vp-p at ~200mA (lots of stages...) Maybe a little transformer before the C-W?
> >
> > For 2000V at 100 uA, i.e. a quarter watt, that might actually work. Triangle
> > wave for lowest output ripple, and a CCFL transformer for high ratio

> Right, at first blush the numbers seem to work. I could use a
> ~2kV/ 100uA power supply, that worked off my function generator.

> I've not done a lot of transformers, a pot core is easy.

A good HV transformer from CCFL surplus seems easiest:

<http://www.ebay.com/itm/1400314-inverter-transformer-for-Samsung-CCFL-backlight-LCD-TV-/151246710786?hash=item233701a802:g:MbkAAOxy69JTFaLb>

Observe the multiple sections of the secondry winding... high voltage and distance
are built into the (odd, elongated) design. Alas, not quick to ship, this item...

> Can't I do fullwave with a FG? ...

> And I have no idea about the triangle wave, (well only a small
> idea about current into a cap), but that all makes it more fun!

Some CCFL transformers are center-tapped (which makes it easy), but not all. Your secondary
might have no center-tap, so for fullwave the easiest is a bridge rectifier (at a kilovolt, yet)
with the negative bit grounded, and then build up three series strings of capacitors; one
side is push, the other is pull, constantly while the triangle is ramping up, then the polarity
swaps when the triangle ramps down, but there's always a diode forward biased attached
to the output (at the end of the middle of the three series strings of capacitors...).

Schematic looks something like this:
<http://www.digikey.com/schemeit/project/c-w-fullwave-TU6DI68200CG/>

It's a rough drawing, but better than ASCII

[Robert Baer]

...or use my Codatron® high voltage zener. Quiet. No cap needed. Caps OK
also.

[Tauno Voipio]

That's what the big boys made us innocent juniors to do. It was an
experience still remembered over more than 60 years ...

--

-TV

[o pere o]

On 20/03/17 01:14, Tim Wescott wrote:
> Or more (volts that is).
>
> Any quick & dirty circuits that'll do this? Something that self-limits
> in current would be nice, but not necessary. I want to test voltage
> regulators. Ideally it'd be battery powered, but that's not a necessity.
>
> Just looking for a quickie one-off.
>
> Thanks.
>

Not a diy solution, but I've had good experiences with Spellman modules
http://www.spellmanhv.com/Products/MS

Pere

[bitrex]

On 03/21/2017 06:27 AM, Tauno Voipio wrote:

>> I guess my dad got to watch while my grandfather peed on one -- he claims
>> he saw it coming but not soon enough to say anything. He also reports
>> thinking it was hilarious, so I'm not so sure about the first claim.
>
>
> That's what the big boys made us innocent juniors to do. It was an
> experience still remembered over more than 60 years ...
>

Yep, it's no great secret that "Real America" is a bunch of sadistic
scumbags.

[Cursitor Doom]

On Tue, 21 Mar 2017 10:54:38 -0400, bitrex wrote:

> Yep, it's no great secret that "Real America" is a bunch of sadistic
> scumbags.

No one is forcing you to live in America. Try moving to Saudi Arabia and
see how that grabs you.

[George Herold]

OK thanks... I don't quite get your circuit. (I need to stare at it a bit more.)

George H.

[bitrex]

They get upset when you touch the women there, though, so probably a
non-starter.

Liberals who say they'd rather live in Canada than the US are definitely
lunatics, though. Get it, loon-atics, like the coin.

[bitrex]

But yeah, I'd definitely like to live somewhere where being forced to
urinate on an electric fence by your peers isn't looked back on like
some kind of precious childhood memory, lol

[dagmarg...@yahoo.com]

What made you think Tauno's American?

Anyway, there's a huge difference between a practical joke and a sadistic
scumbag. One's healthy, the other's sick.

Cheers,
James Arthur

[dagmarg...@yahoo.com]

On Monday, March 20, 2017 at 1:33:46 PM UTC-4, bitrex wrote:
> On 03/20/2017 11:11 AM, dagmarg...@yahoo.com wrote:
> > On Sunday, March 19, 2017 at 8:14:44 PM UTC-4, Tim Wescott wrote:
> >> Or more (volts that is).
> >>
> >> Any quick & dirty circuits that'll do this? Something that self-limits
> >> in current would be nice, but not necessary. I want to test voltage
> >> regulators. Ideally it'd be battery powered, but that's not a necessity.
> >>
> >> Just looking for a quickie one-off.
> >>
> >> Thanks.
> >
> >
> > For a simple start, see LTC AN29 Fig. 49.
> > http://www.linear.com/docs/4122
> >
> > The flyback transformer has been discontinued; I'd suggest adapting the
> > circuit for the Pulse PA-0367A (1:12 transformer) instead.
> >
> > The Wurth 750 032 050 (1:10) is available from Mouser, too.
> >
> > Another approach is to use one of the multi-winding inductors, like
> > this:
> > http://www.edn.com/design/power-management/4334168/1-kV-power-supply-produces-a-continuous-arc
> >
> > Cheers,
> > James Arthur
> >
>
> What about this class C thing, it goes to ~1kV using a single BJT. Add a
> few multiplier stages for 2, should put out 100uA no problem.
>
> OP could wind the xfmr by hand on a small ferrite toroid.
>
> The BJT should probably be at least a 150V 3 amp type. Tank freq is
> around 100kHz
>

<snipped blocking oscillator>

That's cute. I've come to prefer making current-mode blockers, if I'm
going to make a blocker--that makes them a lot less sensitive to
components' variability.

Your circuit reminds me very much of a camera's xenon strobe DC-DC
converter. In fact one of those, surplus, would be a great starting
point. Add a C-W multiplier to the transformer output, done.

http://www.goldmine-elec-products.com/prodinfo.asp?number=G17610

Sam Goldwasser's s.e.repair FAQ has lots of 'em.

http://www.repairfaq.org/sam/samschem.htm#schssi
http://www.repairfaq.org/sam/strbfaq.htm#strbcpc

Cheers,
James Arthur

[Tauno Voipio]

That was a guess some thousands of miles off.

I classify the situation as a practical joke to
teach juniors to think before trusting.

--

-TV

[bitrex]

On 03/21/2017 03:47 PM, dagmarg...@yahoo.com wrote:

> <snipped blocking oscillator>
>
> That's cute. I've come to prefer making current-mode blockers, if I'm
> going to make a blocker--that makes them a lot less sensitive to
> components' variability.
>
> Your circuit reminds me very much of a camera's xenon strobe DC-DC
> converter. In fact one of those, surplus, would be a great starting
> point. Add a C-W multiplier to the transformer output, done.
>
> http://www.goldmine-elec-products.com/prodinfo.asp?number=G17610
>
> Sam Goldwasser's s.e.repair FAQ has lots of 'em.
>
> http://www.repairfaq.org/sam/samschem.htm#schssi
> http://www.repairfaq.org/sam/strbfaq.htm#strbcpc
>
> Cheers,
> James Arthur
>

Nuh uh! Not blocking - AFAIK blocking oscillators rely on xfmr
saturation to cut them off at the end of each cycle.

This one looks to me like it's running regular ol' gain -> positive
feedback -> oscillation, with a tuned tank in the collector and with
regenerative feedback derived from the small secondary winding. The BJT
spends most of its time in class C hard cutoff, popping out for a brief
period every cycle to drive current into the tank to keep it "ringing."

[bitrex]

Well, when the nationalist Right says "Why are you liberals so
sensitive, can't you take a joke" we simply know from hard experience
right where "jokes" lead.

<https://en.wikipedia.org/wiki/Death_of_Brian_Deneke>

<https://en.wikipedia.org/wiki/Murder_of_Sophie_Lancaster>

[bitrex]

I think "Big Willy Style" Sloman posted a document one time that showed
all tanked class C power oscillator topologies were finally materially
equivalent from an analysis standpoint.

The main advantage of the feedback winding for high output voltages
where you're winding the xfmr by hand is that hand winding a
center-tapped arrangement is a pain in the butt.

[bitrex]

I think it's easier to just build a simple 1 transistor power oscillator
on perfboard with a couple stages of multiplication and hand-wind a
little inductor than try to futz around with an "eBay Special" tazer
circuit designed to make over 60kV into doing what I wanted. Could
probably have finished it in the time we spent talking about it;
certainly long before a package from China arrived.

YMMV

[whit3rd]

On Tuesday, March 21, 2017 at 11:54:17 AM UTC-7, George Herold wrote:
> On Tuesday, March 21, 2017 at 1:50:55 AM UTC-4, whit3rd wrote:

> > Some CCFL transformers are center-tapped (which makes it easy), but not all. Your secondary

> > might have no center-tap, so for fullwave the easiest is ...

> OK thanks... I don't quite get your circuit. (I need to stare at it a bit more.)

Actually, this is a better scheme: just throw more hardware at the problem:

<http://www.digikey.com/schemeit/project/centertap-the-hard-way-UE4DKT0203NG/>

The basic Cockcroft-Walton rectifier is halfwave, so you use two to make a fullwave
variant, but you can share half the capacitors (on the 'center leg') instead of duplicating
them.

[Julian Barnes]

On Tue, 21 Mar 2017 15:13:05 -0400, bitrex wrote:

> They get upset when you touch the women there, though, so probably a
> non-starter.

well dont touch 'em, then. whut r u some sort of perv lolz?

[k...@notreal.com]

On Tue, 21 Mar 2017 15:13:05 -0400, bitrex

<bit...@de.lete.earthlink.net> wrote:

>On 03/21/2017 02:49 PM, Cursitor Doom wrote:
>> On Tue, 21 Mar 2017 10:54:38 -0400, bitrex wrote:
>>
>>> Yep, it's no great secret that "Real America" is a bunch of sadistic
>>> scumbags.
>>
>> No one is forcing you to live in America. Try moving to Saudi Arabia and
>> see how that grabs you.
>>
>
>They get upset when you touch the women there, though, so probably a
>non-starter.

They'll get upset when you touch men, too, ShortRex.

[bill....@ieee.org]

Not at all. If you want a really close-coupled centre-tapped pair, you wind it "bifilar" - work out how long a bit of wire you need, cut off two bits a bit long than that, twist them, and wind on the twisted pair.

National Bureau of Standards precision freaks assure us that the two halves of the pair are identical to one part in a billion. You probably need the two bits of wire to come off the same reel for that - reel to reel tolerance on wire resistance is usually +/-2% (which implies +/-1% on diameter).

--
Bill Sloman, Sydney

[Robert Baer]

Since you are in the forest, the ticks become you.

[dagmarg...@yahoo.com]

Oh that's right, I forgot -- simulated transformers don't saturate.

Here, I tweaked it into a blocking version. It gets 1.4kV from +24V instead
of yours making 900V from +48V, and is a bit easier on the base drive.

Version 4
SHEET 1 1380 680
WIRE 64 32 -80 32
WIRE 208 32 208 -16
WIRE 208 32 64 32
WIRE 480 64 304 64
WIRE 656 64 544 64
WIRE 912 64 656 64
WIRE 992 64 912 64
WIRE 1152 64 1056 64
WIRE 1360 64 1152 64
WIRE 208 112 208 32
WIRE 304 112 304 64
WIRE -272 128 -272 96
WIRE -80 128 -80 32
WIRE 64 128 64 32
WIRE 656 128 656 64
WIRE 912 128 912 64
WIRE 1152 128 1152 64
WIRE 1360 128 1360 64
WIRE -272 240 -272 208
WIRE 304 240 304 192
WIRE 656 240 656 192
WIRE 656 240 304 240
WIRE 720 240 656 240
WIRE 752 240 720 240
WIRE 912 240 912 192
WIRE 912 240 816 240
WIRE 1152 240 1152 192
WIRE 1152 240 912 240
WIRE 1232 240 1152 240
WIRE 1360 240 1360 192
WIRE 1360 240 1296 240
WIRE 64 256 64 192
WIRE 208 256 208 192
WIRE 208 256 64 256
WIRE 464 288 320 288
WIRE -80 320 -80 208
WIRE -16 320 -80 320
WIRE 96 320 48 320
WIRE 464 336 464 288
WIRE 1360 336 1360 240
WIRE 720 352 720 240
WIRE 208 368 208 256
WIRE 400 368 320 368
WIRE 656 384 656 240
WIRE -80 416 -80 320
WIRE -32 416 -80 416
WIRE 96 416 96 320
WIRE 96 416 48 416
WIRE 144 416 96 416
WIRE 96 448 96 416
WIRE 720 464 720 432
WIRE -80 480 -80 416
WIRE 96 544 96 512
WIRE 208 560 208 464
WIRE -80 640 -80 544
WIRE 400 640 400 368
WIRE 400 640 -80 640
FLAG 208 -16 Vcc
FLAG 208 560 0
FLAG 464 336 0
FLAG -272 240 0
FLAG -272 96 Vcc
FLAG 1360 336 0
FLAG 656 384 HV_OUT
IOPIN 656 384 Out
FLAG 96 544 0
FLAG 720 464 0
SYMBOL ind2 192 96 R0
WINDOW 3 34 74 Left 2
SYMATTR Value 47µH
SYMATTR InstName L1
SYMATTR SpiceLine Rser=.1
SYMBOL ind2 288 96 R0
SYMATTR InstName L2
SYMATTR Value 1mH
SYMBOL npn 144 368 R0
SYMATTR InstName Q1
SYMATTR Value 2SCR375P
SYMBOL ind2 336 384 R180
WINDOW 0 36 80 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName L3
SYMATTR Value .47µH
SYMBOL cap 48 128 R0
SYMATTR InstName C1
SYMATTR Value 50p
SYMBOL res -96 112 R0
SYMATTR InstName R2
SYMATTR Value 47k
SYMBOL res 64 400 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 220
SYMBOL cap 48 304 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 1n
SYMBOL voltage -272 112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 24
SYMBOL cap -96 480 R0
SYMATTR InstName C3
SYMATTR Value 22n
SYMBOL cap 544 48 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C4
SYMATTR Value 100nF
SYMBOL diode 640 128 R0
WINDOW 3 -114 32 Left 2
SYMATTR Value RFN1L7S
SYMATTR InstName D1
SYMBOL cap 816 224 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C5
SYMATTR Value 100nF
SYMBOL cap 1056 48 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C6
SYMATTR Value 100nF
SYMBOL cap 1296 224 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C7
SYMATTR Value 100nF
SYMBOL diode 928 192 R180
WINDOW 0 24 64 Left 2
WINDOW 3 52 27 Left 2
SYMATTR InstName D2
SYMATTR Value RFN1L7S
SYMBOL diode 1136 128 R0
WINDOW 3 -118 31 Left 2
SYMATTR Value RFN1L7S
SYMATTR InstName D3
SYMBOL diode 1376 192 R180
WINDOW 0 24 64 Left 2
WINDOW 3 58 33 Left 2
SYMATTR InstName D4
SYMATTR Value RFN1L7S
SYMBOL diode 112 512 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D5
SYMBOL res 704 336 R0
SYMATTR InstName R1
SYMATTR Value 10meg
TEXT -392 344 Left 2 !K1 L1 L2 L3 1
TEXT -392 296 Left 2 !.tran 1 startup uic


I'm actually not sure what's flat-topping the flyback voltage--I'd think
it would go higher.

Why doesn't yours have a higher resonance peak?

Cheers,
James Arthur

[Michael A. Terrell]

George Herold wrote:
> On Sunday, March 19, 2017 at 9:01:33 PM UTC-4, Winfield Hill wrote:
>> John Larkin wrote...
>>>
>>> Tim Wescott wrote:
>>>> Any quick & dirty circuits that'll do this? ...

>>>> I want to test voltage regulators.
>>>>

>>>> Just looking for a quickie one-off.
>>>

>>> Ebay copier high voltage supply? Or a used
>>> HV bench supply, which is handy to have around.
>>
>> What, you didn't suggest your Cockcroft-Walton
>> HV multiplier circuit and parts? With higher
>> starting supply voltages it can easily do 2kV.
>
> That was my thought C-W from 120 or 240 AC?
> (Or do you need a faster frequency?)
> Not sure it would be dirty or quick though.


How about this?


10KV High Frequency Transformer Booster Coil Inverter Electric Ignitor

http://www.ebay.com/itm/112312214802


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)