AC Cap Dropper DC Power Supply

Jim Thompson

unread,

Sep 27, 2012, 3:44:00 PM9/27/12

to

Phil Hobbs

unread,

Sep 27, 2012, 6:00:10 PM9/27/12

to

On 09/27/2012 03:44 PM, Jim Thompson wrote:
> AC Cap Dropper DC Power Supply
>
> Anyone know of a clever way to regulate other than the typical
> brute-force zener clamp?
>
> ...Jim Thompson

How about a mag amp? ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

Jim Thompson

unread,

Sep 27, 2012, 6:15:11 PM9/27/12

to

On Thu, 27 Sep 2012 18:00:10 -0400, Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:

>On 09/27/2012 03:44 PM, Jim Thompson wrote:
>> AC Cap Dropper DC Power Supply
>>
>> Anyone know of a clever way to regulate other than the typical
>> brute-force zener clamp?
>>
>> ...Jim Thompson
>
>How about a mag amp? ;)
>
>Cheers
>
>Phil Hobbs

Chewing on some authentic Australian licorice, I almost choked ;-)

Tom Biasi

unread,

Sep 27, 2012, 6:22:58 PM9/27/12

to

On 9/27/2012 3:44 PM, Jim Thompson wrote:
> AC Cap Dropper DC Power Supply
>
> Anyone know of a clever way to regulate other than the typical
> brute-force zener clamp?
>
> ...Jim Thompson
>

A long,long time ago in a place not so far away I used a transformer
made by Sola that had a matched resonant capacitor.

Tom

Jim Thompson

unread,

Sep 27, 2012, 7:29:29 PM9/27/12

to

On Thu, 27 Sep 2012 18:22:58 -0400, Tom Biasi <tomb...@optonline.net>
wrote:

Will it fit in 1" x 1" ?:-)

Tom Biasi

unread,

Sep 27, 2012, 7:44:50 PM9/27/12

to

On 9/27/2012 7:29 PM, Jim Thompson wrote:
> On Thu, 27 Sep 2012 18:22:58 -0400, Tom Biasi <tomb...@optonline.net>
> wrote:
>
>> On 9/27/2012 3:44 PM, Jim Thompson wrote:
>>> AC Cap Dropper DC Power Supply
>>>
>>> Anyone know of a clever way to regulate other than the typical
>>> brute-force zener clamp?
>>>
>>> ...Jim Thompson
>>>
>>
>>
>>
>> A long,long time ago in a place not so far away I used a transformer
>> made by Sola that had a matched resonant capacitor.
>>
>> Tom
>
> Will it fit in 1" x 1" ?:-)
>
> ...Jim Thompson
>

Not hardly. And it was heavy too.

Tom

Charles

unread,

Sep 27, 2012, 7:46:35 PM9/27/12

to

"Jim Thompson" wrote in message
news:8ao9681qiq8lhs3b0...@4ax.com...

On Thu, 27 Sep 2012 18:22:58 -0400, Tom Biasi <tomb...@optonline.net>
wrote:

>On 9/27/2012 3:44 PM, Jim Thompson wrote:
>> AC Cap Dropper DC Power Supply
>>
>> Anyone know of a clever way to regulate other than the typical
>> brute-force zener clamp?
>>
>> ...Jim Thompson
>>
>
>
>
>A long,long time ago in a place not so far away I used a transformer
>made by Sola that had a matched resonant capacitor.
>
>Tom

Will it fit in 1" x 1" ?:-)

No, but that VR method marches on (for select applications).
http://www.generaltransformer.com/transformer/ferroresonant-transformers.htm

Jim Thompson

unread,

Sep 27, 2012, 9:14:41 PM9/27/12

to

On Thu, 27 Sep 2012 19:44:50 -0400, Tom Biasi <tomb...@optonline.net>

wrote:

>On 9/27/2012 7:29 PM, Jim Thompson wrote:
>> On Thu, 27 Sep 2012 18:22:58 -0400, Tom Biasi <tomb...@optonline.net>
>> wrote:
>>
>>> On 9/27/2012 3:44 PM, Jim Thompson wrote:
>>>> AC Cap Dropper DC Power Supply
>>>>
>>>> Anyone know of a clever way to regulate other than the typical
>>>> brute-force zener clamp?
>>>>
>>>> ...Jim Thompson
>>>>
>>>
>>>
>>>
>>> A long,long time ago in a place not so far away I used a transformer
>>> made by Sola that had a matched resonant capacitor.
>>>
>>> Tom
>>
>> Will it fit in 1" x 1" ?:-)
>>
>> ...Jim Thompson
>>
>
>
>
>Not hardly. And it was heavy too.
>
>Tom

I remember them. Nice scheme if you stand the space/weight.

Jamie

unread,

Sep 27, 2012, 11:24:58 PM9/27/12

to

Jim Thompson wrote:

> On Thu, 27 Sep 2012 18:22:58 -0400, Tom Biasi <tomb...@optonline.net>
> wrote:
>
>
>>On 9/27/2012 3:44 PM, Jim Thompson wrote:
>>
>>>AC Cap Dropper DC Power Supply
>>>
>>>Anyone know of a clever way to regulate other than the typical
>>>brute-force zener clamp?
>>>
>>> ...Jim Thompson
>>>
>>
>>
>>
>>A long,long time ago in a place not so far away I used a transformer
>>made by Sola that had a matched resonant capacitor.
>>
>>Tom
>
>
> Will it fit in 1" x 1" ?:-)
>
> ...Jim Thompson

If your looking for a junk don't care 120V low current supply..

this works on the starting cycle and uses only a portion.. it kinds of
semi regulates, it's only good for low current..

120V AC ||
+-------+-------------+-||-GND
| | ||
| V
| -
0.1uf --- |
--- |
| |/
|---------+-| 2N5550
| |>
| |
.-. |
2k | | |
| | +----------+
'-' | |+
| 500u --- |
=== --- .-.
GND | | |
| | | Your Load
=== '-'
GND |
|
===
GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
Like I said, it's junk but it works, you can sim that ...

I think that was around 5 volts out..

Jamie

lang...@fonz.dk

unread,

Sep 28, 2012, 7:27:03 AM9/28/12

to

On 28 Sep., 01:29, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
> On Thu, 27 Sep 2012 18:22:58 -0400, Tom Biasi <tombi...@optonline.net>

> wrote:
>
> >On 9/27/2012 3:44 PM, Jim Thompson wrote:
> >> AC Cap Dropper DC Power Supply
>
> >> Anyone know of a clever way to regulate other than the typical
> >> brute-force zener clamp?
>
> >> ...Jim Thompson
>
> >A long,long time ago in a place not so far away I used a transformer
> >made by Sola that had a matched resonant capacitor.
>
> >Tom
>
> Will it fit in 1" x 1" ?:-)
>

http://www.digikey.com/product-detail/en/VSK-S1-5U/102-2595-ND/3465373

1.33" L x 0.87" W x 0.71" H, universal input, 5V/200mA output

-Lasse

Bob Masta

unread,

Sep 28, 2012, 8:30:19 AM9/28/12

to

On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>AC Cap Dropper DC Power Supply
>
>Anyone know of a clever way to regulate other than the typical
>brute-force zener clamp?

Not sure exactly what you are looking for, but if you are
using caps to drop voltage I'm guessing this is a "cheap and
cheerful"-type application.

I use a super-simple regulator to drop "dead" 9V batteries
down to 1.5V to run various low-drain devices like clocks
and timers. It's just an NPN (2N3904, etc) with collector
from battery, and emitter driving load. Base "reference" is
a green LED to ground, with a selected resistor from base to
collector. Small enough to wire the whole works onto a 9V
battery clip. Lots of variations: More LEDs for higher
output voltage, Darlingtons for more sensitivity/higher
power, etc.

Forward-biased LEDs have super-sharp knees at low currents,
and the parts bins are full of them.

Best regards,

Bob Masta

DAQARTA v7.00
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!

legg

unread,

Sep 28, 2012, 10:57:20 PM9/28/12

to

On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>AC Cap Dropper DC Power Supply
>
>Anyone know of a clever way to regulate other than the typical
>brute-force zener clamp?
>
> ...Jim Thompson

Power level? Input range?

RL

Jim Thompson

unread,

Sep 28, 2012, 9:58:01 PM9/28/12

to

0.8W, Input is 220VAC/50Hz full-wave-rectified.

legg

unread,

Sep 29, 2012, 12:22:46 AM9/29/12

to

On Fri, 28 Sep 2012 18:58:01 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Fri, 28 Sep 2012 21:57:20 -0500, legg <le...@nospam.magma.ca> wrote:
>
>>On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
>><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>>
>>>AC Cap Dropper DC Power Supply
>>>
>>>Anyone know of a clever way to regulate other than the typical
>>>brute-force zener clamp?
>>>
>>> ...Jim Thompson
>>
>>Power level? Input range?
>>
>>RL
>
>0.8W, Input is 220VAC/50Hz full-wave-rectified.
>
> ...Jim Thompson

That's unfortunate, because a lot of tweaking with nonlinear
dielectrics can be done on the lower domestic voltage range. This
reduces the effect of varying input voltage and can reduce the brute
in the force. Also 800mW is a lot to ask of this technique. An ~ 1uF
630VDC/240Vac capacitor hasn't traditionally been considered as small,
consumes a considerable portion of your 1"x1" real estate, and might
only get you 500mW.

Maybe you should mess with a few more numbers, before examining
improvements in the technique? Also, be warned that this isn't a
circuit you can just slip into a pre-existing device that has other
biasing dependencies.

I like the non-simplistic self-oscillating DC-DC stuff. The off-shore
demonstrated capability to produce this circuitry for nothing is the
only upside. Might as well be happy....

RL

Rick

unread,

Sep 29, 2012, 8:18:57 AM9/29/12

to

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in
message news:fblc685tbio5ke4mo...@4ax.com...

The capacitor must go between the AC line and input to the bridge. It uses
the reactance of the capacitor as a dropping resistor.

Jim Thompson

unread,

Sep 29, 2012, 11:44:22 AM9/29/12

to

On Sat, 29 Sep 2012 07:18:57 -0500, "Rick" <rik...@bellsouth.net>
wrote:

>
>"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in
>message news:fblc685tbio5ke4mo...@4ax.com...
>> On Fri, 28 Sep 2012 21:57:20 -0500, legg <le...@nospam.magma.ca> wrote:
>>
>>>On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
>>><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>>>
>>>>AC Cap Dropper DC Power Supply
>>>>
>>>>Anyone know of a clever way to regulate other than the typical
>>>>brute-force zener clamp?
>>>>
>>>> ...Jim Thompson
>>>
>>>Power level? Input range?
>>>
>>>RL
>>
>> 0.8W, Input is 220VAC/50Hz full-wave-rectified.
>>
>> ...Jim Thompson

[snip]

>
>The capacitor must go between the AC line and input to the bridge. It uses
>the reactance of the capacitor as a dropping resistor.
>

Nonsense, all it requires is a _changing_ input.

legg

unread,

Sep 29, 2012, 7:54:28 PM9/29/12

to

On Sat, 29 Sep 2012 08:44:22 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Sat, 29 Sep 2012 07:18:57 -0500, "Rick" <rik...@bellsouth.net>
>wrote:
>
>>
>>"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in
>>message news:fblc685tbio5ke4mo...@4ax.com...
>>> On Fri, 28 Sep 2012 21:57:20 -0500, legg <le...@nospam.magma.ca> wrote:
>>>
>>>>On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
>>>><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>>>>
>>>>>AC Cap Dropper DC Power Supply
>>>>>
>>>>>Anyone know of a clever way to regulate other than the typical
>>>>>brute-force zener clamp?
>>>>>
>>>>> ...Jim Thompson
>>>>
>>>>Power level? Input range?
>>>>
>>>>RL
>>>
>>> 0.8W, Input is 220VAC/50Hz full-wave-rectified.
>>>
>>> ...Jim Thompson
>[snip]
>>
>>The capacitor must go between the AC line and input to the bridge. It uses
>>the reactance of the capacitor as a dropping resistor.
>>
>
>Nonsense, all it requires is a _changing_ input.
>
> ...Jim Thompson

With appropriate discharge paths. If the cap is before the rectifier,
the source can do this, otherwise........

RL

Jim Thompson

unread,

Sep 29, 2012, 7:01:51 PM9/29/12

to

Or a PFC path... that's all I can say right now ;-)

Spehro Pefhany

unread,

Sep 29, 2012, 7:34:02 PM9/29/12

to

On Thu, 27 Sep 2012 12:44:00 -0700, the renowned Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>AC Cap Dropper DC Power Supply
>
>Anyone know of a clever way to regulate other than the typical
>brute-force zener clamp?
>
> ...Jim Thompson

If it's full-wave rectified you can turn a HV part 'off' when the
voltage exceeds your desired output voltage and lose the series cap.
Your output cap need only be as big as a full-wave rectified low
voltage supply would required.

The cap is better with transients most likely, but if it's behind a
bunch of electronics anyway, the above might be a good solution.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

legg

unread,

Sep 29, 2012, 11:05:05 PM9/29/12

to

On Sat, 29 Sep 2012 16:01:51 -0700, Jim Thompson

Who's on first.

RL

Jamie

unread,

Sep 29, 2012, 10:31:47 PM9/29/12

to

You know, Jim really shocks me, he designs IC's and yet, he has this dilemma

Getting information from him is like pulling teeth.. It would be nice
to know the output voltage requirement. We already know the watts (0.8),
but at what voltage on the output?

I offered up a bad idea of a design, just like him asking for
something that should be trivial on his part.

WHen he said a "Cap dropper" I miss read and gave him a "Crap dropper"
or did I?

The circuit I offered up however, works great as a line noise detector. :)

Jamie

Jasen Betts

unread,

Sep 29, 2012, 11:56:49 PM9/29/12

to

On 2012-09-29, Jim Thompson <To-Email-Use-Th...@On-My-Web-Site.com> wrote:
> On Fri, 28 Sep 2012 21:57:20 -0500, legg <le...@nospam.magma.ca> wrote:
>
>>On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
>><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>>
>>>AC Cap Dropper DC Power Supply
>>>
>>>Anyone know of a clever way to regulate other than the typical
>>>brute-force zener clamp?
>>>
>>> ...Jim Thompson
>>
>>Power level? Input range?
>>
>>RL
>
> 0.8W, Input is 220VAC/50Hz full-wave-rectified.
>
> ...Jim Thompson

you're wanting to run it off the ripple?
the higher frequency will help a bit, but the voltage swing will be
much less, less predictable too I expect.

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---

Jim Thompson

unread,

Sep 30, 2012, 12:37:23 AM9/30/12

to

Costello :-)

But that's the real problem: egg-chicken-egg... who runs the control
loop?

Message has been deleted

Spehro Pefhany

unread,

Sep 30, 2012, 3:20:06 AM9/30/12

to

On Sat, 29 Sep 2012 23:56:07 -0500, the renowned flipper
<fli...@fish.net> wrote:

>
>I used a variation of that to make a 12.6V (DC) tube heater supply
>from a 30V transformer. I call it a "pulse regulator."
>
>The series cap is still a good idea because the charge pulse is going
>to be limited by 'something', even if it's only Rdson, and the cap
>would cut down on the peak current spikes.

Then how about clamping the cap low side to ground after the output
filter cap has gotten enough juice? Need another series switch or
diode, of course. The power dissipation would be much less doing it
that way since i*Rds(on) should be << Vout.

Message has been deleted

John Larkin

unread,

Sep 30, 2012, 1:29:48 PM9/30/12

to

On Sat, 29 Sep 2012 19:34:02 -0400, Spehro Pefhany
<spef...@interlogDOTyou.knowwhat> wrote:

>On Thu, 27 Sep 2012 12:44:00 -0700, the renowned Jim Thompson
><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>
>>AC Cap Dropper DC Power Supply
>>
>>Anyone know of a clever way to regulate other than the typical
>>brute-force zener clamp?
>>
>> ...Jim Thompson
>
>If it's full-wave rectified you can turn a HV part 'off' when the
>voltage exceeds your desired output voltage and lose the series cap.
>Your output cap need only be as big as a full-wave rectified low
>voltage supply would required.
>
>The cap is better with transients most likely, but if it's behind a
>bunch of electronics anyway, the above might be a good solution.
>
>
>Best regards,
>Spehro Pefhany

The series current-limiting cap dissipates no power, so it can be
shorted by a low voltage switch. If it drives, say, the input of a
bridge rectifier or a 2-diode restore thing, short the input of that.
It becomes a bang-bang regulator. If the controller is to be a custom
IC, a modest amount of complexity is free, so some intelligent
zero-crossing thing would be appropriate. But just dumb bang-bang
ought to work.

This is one variation:

https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg

The first diode can be the fet's substrate diode, saving one part.

This is like an alternator regulator that shorts the alternator output
with a triac, to get regulation.

People often add a series resistor, for spike protection, and that
will dissipate some power, but no more than it would with a zener
shunt regulator.

Spehro Pefhany

unread,

Sep 30, 2012, 2:30:56 PM9/30/12

to

On Sun, 30 Sep 2012 10:29:48 -0700, the renowned John Larkin
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:

>
>
>The series current-limiting cap dissipates no power, so it can be
>shorted by a low voltage switch. If it drives, say, the input of a
>bridge rectifier or a 2-diode restore thing, short the input of that.
>It becomes a bang-bang regulator. If the controller is to be a custom
>IC, a modest amount of complexity is free, so some intelligent
>zero-crossing thing would be appropriate. But just dumb bang-bang
>ought to work.

Yup, that's pretty much what I had in mind, I don't think you need the
left diode- either the body diode or turning the MOSFET on will work
(assuming custom ICs are like discretes, which they may not be).

Making the other diode into a synchronous MOSFET rectifier might be
worth it.

Jamie

unread,

Sep 30, 2012, 5:21:30 PM9/30/12

to

that looks just like a charging circuit I tried once, only I didn't have
a ripple cap. All I had was a - feed back zener and a bjt with a
by pass diode, at the time. I only used a 24V AC source but the idea was
to allow it to have a constant short with out internal heating.

I wanted a pulse type of charging instead of constant DC.

10u
600V SI 30 Hz pulse out
||
-||-+--+------+----+->|-+-+---------------------+
|| | | +
AC line in | | z Max Voltage limit Diode
| | A
| | |
surge clamp z | |
A + HV NPN V Back flow stopper
-(diode too) | | -
5 watt + \| |
| |+--------+-------+
| <| .-. +
| + | | ---
| | | | ---
| | '+' +
+------+-----------++------+

|
===
GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

Even though that works, I wouldn't suggest using AC over 48 volts
unless you have it totally enclosed.

Never thought of trying a mosfet for that, I have seen some that have
zenering substrate diodes. Those can do the job of both the required
diode and the noise pulse that may exceed the fets voltage.

If I remember there was a little (-) voltage coming back through the
collector but it didn't seem to bother the rest of it.

Jamie

Jasen Betts

unread,

Oct 1, 2012, 2:00:24 AM10/1/12

to

On 2012-09-30, John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:

> The series current-limiting cap dissipates no power, so it can be
> shorted by a low voltage switch. If it drives, say, the input of a
> bridge rectifier or a 2-diode restore thing, short the input of that.
> It becomes a bang-bang regulator. If the controller is to be a custom
> IC, a modest amount of complexity is free, so some intelligent
> zero-crossing thing would be appropriate. But just dumb bang-bang
> ought to work.
>
>
> This is one variation:
>
> https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg

inrush current will destroy it.

P E Schoen

unread,

Oct 1, 2012, 3:48:44 AM10/1/12

to

"Jim Thompson" wrote in message

news:l1jf68dgqpvpq5ef6...@4ax.com...

> But that's the real problem: egg-chicken-egg...

Of course it was the egg that came first. All chickens come from eggs. But
not all eggs come from chickens. The first chicken probably emerged from a
reptile egg.

Another answer is that neither the egg nor the chicken came first - it was
the rooster!

Paul
www.muttleydog.com

Tom Del Rosso

unread,

Oct 1, 2012, 6:28:31 AM10/1/12

to

P E Schoen wrote:
> "Jim Thompson" wrote in message
> news:l1jf68dgqpvpq5ef6...@4ax.com...
>
> > But that's the real problem: egg-chicken-egg...
>
> Of course it was the egg that came first. All chickens come from
> eggs. But not all eggs come from chickens. The first chicken probably
> emerged from a reptile egg.

It came from a bird similar to a chicken.

--

Reply in group, but if emailing add one more
zero, and remove the last word.

Michael A. Terrell

unread,

Oct 1, 2012, 8:47:59 AM10/1/12

to

Tom Del Rosso wrote:
>
> P E Schoen wrote:
> > "Jim Thompson" wrote in message
> > news:l1jf68dgqpvpq5ef6...@4ax.com...
> >
> > > But that's the real problem: egg-chicken-egg...
> >
> > Of course it was the egg that came first. All chickens come from
> > eggs. But not all eggs come from chickens. The first chicken probably
> > emerged from a reptile egg.
>
> It came from a bird similar to a chicken.

Where did that bird come from?

Les Cargill

unread,

Oct 1, 2012, 9:00:24 AM10/1/12

to

From another bird. Dinosaur DNA has latent "feather subroutines"
that were "exposed" by evolutionary processes.

http://evolution.berkeley.edu/evosite/evo101/VSpeciation.shtml

--
Les Cargill

lang...@fonz.dk

unread,

Oct 1, 2012, 9:36:55 AM10/1/12

to

On 30 Sep., 01:34, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat>
wrote:

> On Thu, 27 Sep 2012 12:44:00 -0700, the renowned Jim Thompson
>

> <To-Email-Use-The-Envelope-I...@On-My-Web-Site.com> wrote:
> >AC Cap Dropper DC Power Supply
>
> >Anyone know of a clever way to regulate other than the typical
> >brute-force zener clamp?
>
> > ...Jim Thompson
>
> If it's full-wave rectified you can turn a HV part 'off' when the
> voltage exceeds your desired output voltage and lose the series cap.
> Your output cap need only be as big as a full-wave rectified low
> voltage supply would required.
>
> The cap is better with transients most likely, but if it's behind a
> bunch of electronics anyway, the above might be a good solution.
>

I'm sure I remember seeing a chip made for standby supply that did
something
like that

something real simple maybe, series pfet, clamp gate when input
exceeds
desired output

-Lasse

John Larkin

unread,

Oct 1, 2012, 11:34:46 AM10/1/12

to

On 1 Oct 2012 06:00:24 GMT, Jasen Betts <ja...@xnet.co.nz> wrote:

>On 2012-09-30, John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
>> The series current-limiting cap dissipates no power, so it can be
>> shorted by a low voltage switch. If it drives, say, the input of a
>> bridge rectifier or a 2-diode restore thing, short the input of that.
>> It becomes a bang-bang regulator. If the controller is to be a custom
>> IC, a modest amount of complexity is free, so some intelligent
>> zero-crossing thing would be appropriate. But just dumb bang-bang
>> ought to work.
>>
>>
>> This is one variation:
>>
>> https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg
>
>inrush current will destroy it.

As I mentioned, and you snipped, people often include a series
resistor to limit transient currents.

C-limited supplies are commonly used for things like LED night-lights.
It does take good engineering to do them right.

John Fields

unread,

Oct 1, 2012, 7:03:56 PM10/1/12

to

On Mon, 01 Oct 2012 08:34:46 -0700, John Larkin
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:

>On 1 Oct 2012 06:00:24 GMT, Jasen Betts <ja...@xnet.co.nz> wrote:
>
>>On 2012-09-30, John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>
>>> The series current-limiting cap dissipates no power,

---
Not quite true, since no dielectric is lossless.
---

>>>so it can be shorted by a low voltage switch.

---
It can be but, depending on when in the cycle the switch turns on,
things might get grim.
---

>>>If it drives, say, the input of a
>>> bridge rectifier or a 2-diode restore thing, short the input of that.

---
Still, depending on when in the cycle the switch turns on, things
might get grim.
---

>>> It becomes a bang-bang regulator. If the controller is to be a custom
>>> IC, a modest amount of complexity is free, so some intelligent
>>> zero-crossing thing would be appropriate. But just dumb bang-bang
>>> ought to work.

---
From the ridiculous to the sublime to the ridiculous!
---

>>> This is one variation:
>>>
>>> https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg
>>
>>inrush current will destroy it.
>
>As I mentioned, and you snipped, people often include a series
>resistor to limit transient currents.

---
And yet your circuit shows that some people - who should know better -
don't.
---

>C-limited supplies are commonly used for things like LED night-lights.

---
C = current?

Since resistors are way cheaper than caps, my feeling is that using
cheap 2mA LEDs in parallel opposition with a 1/4 watt resistor in
series with 120V mains will do the trick.

You?
---

>It does take good engineering to do them right.

---
Then you don't make LED night-lights, I take it?

--
JF

John Larkin

unread,

Oct 2, 2012, 2:08:51 PM10/2/12

to

On Mon, 01 Oct 2012 18:03:56 -0500, John Fields
<jfi...@austininstruments.com> wrote:

>On Mon, 01 Oct 2012 08:34:46 -0700, John Larkin
><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
>>On 1 Oct 2012 06:00:24 GMT, Jasen Betts <ja...@xnet.co.nz> wrote:
>>
>>>On 2012-09-30, John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>>
>>>> The series current-limiting cap dissipates no power,
>
>---
>Not quite true, since no dielectric is lossless.
>---
>
>>>>so it can be shorted by a low voltage switch.
>
>---
>It can be but, depending on when in the cycle the switch turns on,
>things might get grim.
>---
>
>>>>If it drives, say, the input of a
>>>> bridge rectifier or a 2-diode restore thing, short the input of that.
>
>---
>Still, depending on when in the cycle the switch turns on, things
>might get grim.

Bad engineering can create grim outcomes. Better to not do that.

>---
>
>>>> It becomes a bang-bang regulator. If the controller is to be a custom
>>>> IC, a modest amount of complexity is free, so some intelligent
>>>> zero-crossing thing would be appropriate. But just dumb bang-bang
>>>> ought to work.
>
>---
>From the ridiculous to the sublime to the ridiculous!
>---
>
>>>> This is one variation:
>>>>
>>>> https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg
>>>
>>>inrush current will destroy it.
>>
>>As I mentioned, and you snipped, people often include a series
>>resistor to limit transient currents.
>
>---
>And yet your circuit shows that some people - who should know better -
>don't.

Idiot whining again. That's pretty much your skill set.

>---
>
>>C-limited supplies are commonly used for things like LED night-lights.
>
>---
>C = current?

Idiot whining again.

>
>Since resistors are way cheaper than caps, my feeling is that using
>cheap 2mA LEDs in parallel opposition with a 1/4 watt resistor in
>series with 120V mains will do the trick.

A 1/4 watt resistor dissipating 1/4 watt in a confined space won't
last long. At 240 volts, 2 mA dissipates a half watt.

>
>You?
>---
>
>>It does take good engineering to do them right.
>
>---
>Then you don't make LED night-lights, I take it?

What an ass you are.

I certainly don't make night lights for production. My stuff sells for
kilobucks, not cents. I have done a few for myself, for personal
applications.

I assume that JT has some commercial application in mind, with a low
vampire power budget, and has no ideas of his own.

--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

John Larkin

unread,

Oct 2, 2012, 2:12:39 PM10/2/12

to

That looks equivalent to a shunt zener. The NPN runs in linear mode
and gets hot.

Jim Thompson

unread,

Oct 2, 2012, 2:39:03 PM10/2/12

to

On Tue, 02 Oct 2012 11:08:51 -0700, John Larkin
<jla...@highlandtechnology.com> wrote:

[snip]

>
>I assume that JT has some commercial application in mind, with a low
>vampire power budget, and has no ideas of his own.

Yep, extremely low power, switcher start-up circuitry, and I certainly
do have ideas of my own: controlled surge, then, once switcher starts,
auxiliary supply is turned off _completely_, no capacitor current at
all... done with a readily available 15 cent part.

Students! What is the beginner's error in this...

https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg ?:-)

Other than it being general Larkin crap ;-)

Jamie

unread,

Oct 2, 2012, 5:47:20 PM10/2/12

to

Not really, the idea is to select the dropping cap to deliver only
what you need and the excess is shunted via the NPN. Excess being no load or
topped off battery after charge.

Your use of a mosfet in the same place being regulated in linear mode
would also do the same, it could even oscillate if the ripple wasn't
properly handled in the - feed back. I suppose one could use a buck
switcher to reduce heat if that is an issue.

The charger I made didn't generate any heat that was even noticeable and
that was with no heat sink. I don't suggest such designs due to their
nature in design, they aren't that safe..

Jamie

John Larkin

unread,

Oct 2, 2012, 5:46:01 PM10/2/12

to

On Tue, 02 Oct 2012 17:47:20 -0400, Jamie

It does the same as a single zener, but is more complex.

>
> Your use of a mosfet in the same place being regulated in linear mode
>would also do the same,

No, my circuit goes into zero dissipation mode when it doesn't need to
charge the cap. The low-voltage shunt mosfet (or NPN) could be
integrated into a controller chip. Maybe Jim can patent the idea.

Jamie

unread,

Oct 2, 2012, 7:17:45 PM10/2/12

to

Body diode?

Jamie

Jim Thompson

unread,

Oct 2, 2012, 8:50:14 PM10/2/12

to

On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>AC Cap Dropper DC Power Supply
>
>Anyone know of a clever way to regulate other than the typical
>brute-force zener clamp?
>
> ...Jim Thompson

I ended up with this...

http://www.analog-innovations.com/SED/SingleLoopController_00056_MOD3.pdf

Using a depletion-mode NMOS FET.

I have a version I personally liked better that used a cheapy TRIAC
under DDROP3, but I could not find a way to get some "free" power for
the gate... needed while pumping, goes away when overcome by the
switcher coming on line.

(This is a wild high PFC, high efficiency dude, where the customer is
squeezing me for milliwatts :-)

John Larkin

unread,

Oct 2, 2012, 10:21:30 PM10/2/12

to

On Tue, 02 Oct 2012 19:17:45 -0400, Jamie

As Spehro suggested, the fet can be turned on when the current swings
negative, which shorts the body diode and improves efficiency a tiny
bit more.

--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

Message has been deleted

John Larkin

unread,

Oct 2, 2012, 11:31:25 PM10/2/12

to

On Tue, 02 Oct 2012 17:50:14 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>
>>AC Cap Dropper DC Power Supply
>>
>>Anyone know of a clever way to regulate other than the typical
>>brute-force zener clamp?
>>
>> ...Jim Thompson
>
>I ended up with this...
>
>http://www.analog-innovations.com/SED/SingleLoopController_00056_MOD3.pdf
>
>Using a depletion-mode NMOS FET.
>
>I have a version I personally liked better that used a cheapy TRIAC
>under DDROP3, but I could not find a way to get some "free" power for
>the gate... needed while pumping, goes away when overcome by the
>switcher coming on line.
>
>(This is a wild high PFC, high efficiency dude, where the customer is
>squeezing me for milliwatts :-)
>
> ...Jim Thompson

That's crazy. Not only is it expensive, once the 24 volt supply kicks
in, it dissipates most of a watt, doing nothing.

Boy, did I just save you some embarassment.

Jim Thompson

unread,

Oct 3, 2012, 12:11:23 AM10/3/12

to

On Tue, 02 Oct 2012 20:31:25 -0700, John Larkin
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:

>On Tue, 02 Oct 2012 17:50:14 -0700, Jim Thompson
><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>
>>On Thu, 27 Sep 2012 12:44:00 -0700, Jim Thompson
>><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>>
>>>AC Cap Dropper DC Power Supply
>>>
>>>Anyone know of a clever way to regulate other than the typical
>>>brute-force zener clamp?
>>>
>>> ...Jim Thompson
>>
>>I ended up with this...
>>
>>http://www.analog-innovations.com/SED/SingleLoopController_00056_MOD3.pdf
>>
>>Using a depletion-mode NMOS FET.
>>
>>I have a version I personally liked better that used a cheapy TRIAC
>>under DDROP3, but I could not find a way to get some "free" power for
>>the gate... needed while pumping, goes away when overcome by the
>>switcher coming on line.
>>
>>(This is a wild high PFC, high efficiency dude, where the customer is
>>squeezing me for milliwatts :-)
>>
>> ...Jim Thompson
>
>That's crazy. Not only is it expensive, once the 24 volt supply kicks
>in, it dissipates most of a watt, doing nothing.
>
>Boy, did I just save you some embarassment.

You're so ignorant you don't know how it works. Thanks for the
exhibition!

John Larkin

unread,

Oct 3, 2012, 12:20:47 AM10/3/12

to

On Tue, 02 Oct 2012 21:11:23 -0700, Jim Thompson

Well, how much power do R1, R2, the TL431, and ROFF dissipate once the
main supply is up?

Harder question: what's the worst-case dissipation of the fet if the
main supply doesn't come up, like if the load is shorted or something?

Jim Thompson

unread,

Oct 3, 2012, 1:08:05 AM10/3/12

to

On Tue, 02 Oct 2012 21:20:47 -0700, John Larkin

Bwahahahahaha! You lost the thread... actually two threads... and a
controller chip...

Follow your own advice... do your own searching ;-)

John Larkin

unread,

Oct 3, 2012, 1:12:18 AM10/3/12

to

On Tue, 02 Oct 2012 22:08:05 -0700, Jim Thompson

How much power do R1, R2, the TL431, and ROFF dissipate once the
main supply is up?

Jim Thompson

unread,

Oct 3, 2012, 10:42:51 AM10/3/12

to

On Tue, 02 Oct 2012 21:20:47 -0700, John Larkin

It was "my bad" to have emulated the main supply with a pulse
source... doesn't work that way at all, but I can't show the
customer's circuitry.

In actual practice a PFC/PWM chip comes alive and the switcher starts.
But that "20V" sags since the charge pump can only support ~24mA.

The switcher takes over at 14.5V (about 250ms into the action), the
FET gate is pulled low to shut off the wasted power. The gate
resistor is actually 220K, but the demo TL431 won't work (because of
Iq) to show how "regulation" might be accomplished.

>
>Harder question: what's the worst-case dissipation of the fet if the
>main supply doesn't come up, like if the load is shorted or something?

You are trying to amuse yourself by throwing sand in the air. But you
don't understand how it works. Will some first year EE student
explain it on Larkin ?:-)

John Larkin

unread,

Oct 3, 2012, 11:29:37 AM10/3/12

to

On Wed, 03 Oct 2012 07:42:51 -0700, Jim Thompson

I was thinking about that, specifically where that idealized 300
volt-peak full-wave-rectified waveform came from. If it is through
diodes, there's no pull-down to pump the series RC thing; if it also
drives a 24-volt non-PFC switcher front-end, you won't get that
waveform. If the startup circuit has to be working before a main PFC
switcher starts up, there are all sorts of interesting tangles. If the
switcher starts up on its own, what's this circuit for? Standby power
for some controls? It would still have to work when the PFC was down.

>
>In actual practice a PFC/PWM chip comes alive and the switcher starts.
>But that "20V" sags since the charge pump can only support ~24mA.
>
>The switcher takes over at 14.5V (about 250ms into the action), the
>FET gate is pulled low to shut off the wasted power. The gate
>resistor is actually 220K, but the demo TL431 won't work (because of
>Iq) to show how "regulation" might be accomplished.

Right. ROFF is obviously over-constrained, hence my question about
power consumption, which you elected to not answer. There's no ROFF
value that works sensibly. A much simpler circuit would work.

Does this rig have to work from 90 to 264 volts AC? That, and the Idss
spread, gets interesting.

>
>>
>>Harder question: what's the worst-case dissipation of the fet if the
>>main supply doesn't come up, like if the load is shorted or something?
>
>You are trying to amuse yourself by throwing sand in the air. But you
>don't understand how it works. Will some first year EE student
>explain it on Larkin ?:-)

I understand how it doesn't work. And so far, it doesn't.

You've made a pretty quick transition from "I ended up with this..."
to "my bad." But you're not done yet.

ps - the answer is just about 1 watt lost, with your values of R1, R2,
the TL431, and ROFF. That is, for the record, about 1000 of your
customer's milliwatts.

Keep trying.

Jim Thompson

unread,

Oct 3, 2012, 11:49:45 AM10/3/12

to

On Wed, 03 Oct 2012 08:29:37 -0700, John Larkin

My fault for trying to demo without telling ;-)

There's roughly 400mW consumed while bringing up the switcher. Drops
to ~1mW when turned off.

If the load is shorted ?:-) 212mW in RDROP, 31.9mW in the FET. See,
you clearly don't understand how these things work :-)

John Larkin

unread,

Oct 3, 2012, 12:29:47 PM10/3/12

to

On Wed, 03 Oct 2012 08:49:45 -0700, Jim Thompson

You always brag about designing great circuits without "telling." You
troll for ideas, then hide behind "proprietary" when you do settle on
something... even if you got the ideas here.

>
>There's roughly 400mW consumed while bringing up the switcher. Drops
>to ~1mW when turned off.

Then you have some other circuitry that specifically turns off the
startup supply, that is not shown in the circuit that you posted here.
What is it?

Your circuit is complex. Something much simpler would work, and would
go to very low power all by itself once the main switcher comes up.

>
>If the load is shorted ?:-) 212mW in RDROP, 31.9mW in the FET. See,
>you clearly don't understand how these things work :-)

Is that worst-case? The fet Idss is min 20 mA, typ 80, no specified
max. There is some value of Idss that results in the maximum power
dissipation. What is that value, and what is the dissipation? You
should be able to tease Idss to dump around a watt in the fet, which
is fine if you heat sink it.

Jim Thompson

unread,

Oct 3, 2012, 1:08:16 PM10/3/12

to

On Wed, 03 Oct 2012 09:29:47 -0700, John Larkin
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:

>On Wed, 03 Oct 2012 08:49:45 -0700, Jim Thompson
><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>
>>On Wed, 03 Oct 2012 08:29:37 -0700, John Larkin
>><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>

[snip]

>>>Keep trying.
>>
>>My fault for trying to demo without telling ;-)
>
>You always brag about designing great circuits without "telling." You
>troll for ideas, then hide behind "proprietary" when you do settle on
>something... even if you got the ideas here.
>
>>
>>There's roughly 400mW consumed while bringing up the switcher. Drops
>>to ~1mW when turned off.
>
>
>Then you have some other circuitry that specifically turns off the
>startup supply, that is not shown in the circuit that you posted here.
>What is it?
>
>Your circuit is complex. Something much simpler would work, and would
>go to very low power all by itself once the main switcher comes up.

What's "complex" about it? I need to support 20V at 15mA-20mA for
250ms.

>
>
>>
>>If the load is shorted ?:-) 212mW in RDROP, 31.9mW in the FET. See,
>>you clearly don't understand how these things work :-)
>
>Is that worst-case? The fet Idss is min 20 mA, typ 80, no specified
>max. There is some value of Idss that results in the maximum power
>dissipation. What is that value, and what is the dissipation? You
>should be able to tease Idss to dump around a watt in the fet, which
>is fine if you heat sink it.

"should be" is not an engineering term. My wife uses that term
"should be" a lot while referring to the present administration.
Annoys the hell out of me. We "should be" a Representative Republic,
but we're a dictatorship, the other branches of government are sitting
on their hands and letting Obama do everything by executive order :-(

John Larkin

unread,

Oct 3, 2012, 1:42:54 PM10/3/12

to

On Wed, 03 Oct 2012 10:08:16 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Wed, 03 Oct 2012 09:29:47 -0700, John Larkin
><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>
>>On Wed, 03 Oct 2012 08:49:45 -0700, Jim Thompson
>><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>>
>>>On Wed, 03 Oct 2012 08:29:37 -0700, John Larkin
>>><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>>
>[snip]
>>>>Keep trying.
>>>
>>>My fault for trying to demo without telling ;-)
>>
>>You always brag about designing great circuits without "telling." You
>>troll for ideas, then hide behind "proprietary" when you do settle on
>>something... even if you got the ideas here.
>>
>>>
>>>There's roughly 400mW consumed while bringing up the switcher. Drops
>>>to ~1mW when turned off.
>>
>>
>>Then you have some other circuitry that specifically turns off the
>>startup supply, that is not shown in the circuit that you posted here.
>>What is it?
>>
>>Your circuit is complex. Something much simpler would work, and would
>>go to very low power all by itself once the main switcher comes up.
>
>What's "complex" about it? I need to support 20V at 15mA-20mA for
>250ms.

It has a lot of parts. And you won't address the 1-watt dissipation
issue.

>
>>
>>
>>>
>>>If the load is shorted ?:-) 212mW in RDROP, 31.9mW in the FET. See,
>>>you clearly don't understand how these things work :-)
>>
>>Is that worst-case? The fet Idss is min 20 mA, typ 80, no specified
>>max. There is some value of Idss that results in the maximum power
>>dissipation. What is that value, and what is the dissipation? You
>>should be able to tease Idss to dump around a watt in the fet, which
>>is fine if you heat sink it.
>
>"should be" is not an engineering term. My wife uses that term
>"should be" a lot while referring to the present administration.
>Annoys the hell out of me. We "should be" a Representative Republic,
>but we're a dictatorship, the other branches of government are sitting
>on their hands and letting Obama do everything by executive order :-(
>
> ...Jim Thompson

You are obligated to find the maximum power dissipation point as a
function of possible Idss values, and to heatsink such that nothing
catches fire.

If the design is for universal, CE-tested use, AC line voltage can go
to 264 RMS. That's 373 peak. In that case, the maximum fet dissipation
can be teased well over 1 watt; try it. That fet is rated 1.8 watts
max. If you sim one case, with nominal line voltage and typical Idss,
you are taking risks. Test lab time is expensive; product recalls and
fires are more expensive.

Your sim seems to assume 240 line voltage.

--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com

http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom laser drivers and controllers

Photonics and fiberoptic TTL data links

Jim Thompson

unread,

Oct 3, 2012, 2:26:51 PM10/3/12

to

What 1-Watt dissipation issue? Just because you made up some
bull-shit issue doesn't make it real.

>
>>
>>>
>>>
>>>>
>>>>If the load is shorted ?:-) 212mW in RDROP, 31.9mW in the FET. See,
>>>>you clearly don't understand how these things work :-)
>>>
>>>Is that worst-case? The fet Idss is min 20 mA, typ 80, no specified
>>>max. There is some value of Idss that results in the maximum power
>>>dissipation. What is that value, and what is the dissipation? You
>>>should be able to tease Idss to dump around a watt in the fet, which
>>>is fine if you heat sink it.
>>
>>"should be" is not an engineering term. My wife uses that term
>>"should be" a lot while referring to the present administration.
>>Annoys the hell out of me. We "should be" a Representative Republic,
>>but we're a dictatorship, the other branches of government are sitting
>>on their hands and letting Obama do everything by executive order :-(
>>
>> ...Jim Thompson
>
>You are obligated to find the maximum power dissipation point as a
>function of possible Idss values, and to heatsink such that nothing
>catches fire.
>
>If the design is for universal, CE-tested use, AC line voltage can go
>to 264 RMS. That's 373 peak. In that case, the maximum fet dissipation
>can be teased well over 1 watt; try it. That fet is rated 1.8 watts
>max. If you sim one case, with nominal line voltage and typical Idss,
>you are taking risks. Test lab time is expensive; product recalls and
>fires are more expensive.
>
>Your sim seems to assume 240 line voltage.

Poor baby! Go sit in the corner and suck your thumb.

Jim Thompson

unread,

Oct 3, 2012, 2:49:26 PM10/3/12

to

On Wed, 03 Oct 2012 10:42:54 -0700, John Larkin
<jla...@highlandtechnology.com> wrote:

[snip]

>
>If the design is for universal, CE-tested use, AC line voltage can go
>to 264 RMS. That's 373 peak. In that case, the maximum fet dissipation
>can be teased well over 1 watt; try it. That fet is rated 1.8 watts
>max. If you sim one case, with nominal line voltage and typical Idss,
>you are taking risks. Test lab time is expensive; product recalls and
>fires are more expensive.
>
>Your sim seems to assume 240 line voltage.

It's down-right amusing, YOU lecturing me on rigorous simulation. I
often do 45 PVT corners.

YOU, You post nothing but vague crap.

Once I decide on a configuration I'll beat the crap out of it to make
sure it's a valid design.

Go sit in the corner and suck your thumb and contemplate how many
other ways you can think of to pimp yourself >:-)

John Larkin

unread,

Oct 3, 2012, 4:19:47 PM10/3/12

to

On Wed, 03 Oct 2012 11:26:51 -0700, Jim Thompson

In the PDF that you posted, when the startup circuit is back-fed to 23
volts or so by the main switcher, the parts that I've named dissipate
about one watt. ROFF alone burns over 800 mW. If you have a workaround
for that, show it.

http://www.analog-innovations.com/SED/SingleLoopController_00056_MOD3.pdf

Why can't you see this?

>
>>
>>>
>>>>
>>>>
>>>>>
>>>>>If the load is shorted ?:-) 212mW in RDROP, 31.9mW in the FET. See,
>>>>>you clearly don't understand how these things work :-)
>>>>
>>>>Is that worst-case? The fet Idss is min 20 mA, typ 80, no specified
>>>>max. There is some value of Idss that results in the maximum power
>>>>dissipation. What is that value, and what is the dissipation? You
>>>>should be able to tease Idss to dump around a watt in the fet, which
>>>>is fine if you heat sink it.
>>>
>>>"should be" is not an engineering term. My wife uses that term
>>>"should be" a lot while referring to the present administration.
>>>Annoys the hell out of me. We "should be" a Representative Republic,
>>>but we're a dictatorship, the other branches of government are sitting
>>>on their hands and letting Obama do everything by executive order :-(
>>>
>>> ...Jim Thompson
>>
>>You are obligated to find the maximum power dissipation point as a
>>function of possible Idss values, and to heatsink such that nothing
>>catches fire.
>>
>>If the design is for universal, CE-tested use, AC line voltage can go
>>to 264 RMS. That's 373 peak. In that case, the maximum fet dissipation
>>can be teased well over 1 watt; try it. That fet is rated 1.8 watts
>>max. If you sim one case, with nominal line voltage and typical Idss,
>>you are taking risks. Test lab time is expensive; product recalls and
>>fires are more expensive.
>>
>>Your sim seems to assume 240 line voltage.
>
>Poor baby! Go sit in the corner and suck your thumb.

OK, you can't calculate the worst-case fet dissipation.

>
> ...Jim Thompson

Hey, spin the design as many times as your customer can stand. And
have lots of liability insurance, 'cause you're going to be on the
painful end of the expert-witness game. And you're being this sloppy,
in public, archived forever.

John Fields

unread,

Oct 3, 2012, 4:39:58 PM10/3/12

to

On Tue, 02 Oct 2012 11:08:51 -0700, John Larkin

I'm the idiot???

You claim that people often include a series resistor to limit
transient currents and yet, the circuit you show - which seems to be
susceptible to damage from transients - doesn't include the resistor
you claim should be there.

---

>>>C-limited supplies are commonly used for things like LED night-lights.
>>
>>---
>>C = current?
>
>Idiot whining again.

---
Then what does C-limited mean?

Be careful, that's a trick question. :-)
---

>>Since resistors are way cheaper than caps, my feeling is that using
>>cheap 2mA LEDs in parallel opposition with a 1/4 watt resistor in
>>series with 120V mains will do the trick.
>
>A 1/4 watt resistor dissipating 1/4 watt in a confined space won't
>last long.

---
Could you be a little less specific, please?
---

At 240 volts, 2 mA dissipates a half watt.

---
Oh, goody!!!

You know Ohm's law too!!!
---

>>You?
>>---
>>
>>>It does take good engineering to do them right.
>>
>>---
>>Then you don't make LED night-lights, I take it?
>
>What an ass you are.

---
Ah, then the inference didn't go over your head?
---

>I certainly don't make night lights for production. My stuff sells for
>kilobucks, not cents. I have done a few for myself, for personal
>applications.

---
Wowie zowie!

How ever so kewl!
---

>I assume that JT has some commercial application in mind, with a low
>vampire power budget, and has no ideas of his own.

---
With no ideas of his own?

I think the US government would quarrel with you on that one, and win.

--
JF

Jim Thompson

unread,

Oct 3, 2012, 5:18:09 PM10/3/12

to

On Wed, 03 Oct 2012 13:19:47 -0700, John Larkin

I know you're a pimp, but I don't think you're dense... just a dense
asshole. That's not the real circuit. I walked you thru that this
morning. Now go away.

John Larkin

unread,

Oct 3, 2012, 5:55:09 PM10/3/12

to

On Wed, 03 Oct 2012 15:39:58 -0500, John Fields

I said in plain English that a series resistor might be appropriate.
In some cases, like a clean low-voltage AC source, it might not be
needed. I've done lots of voltage-doubler type supplies with no series
R.

John Larkin

unread,

Oct 3, 2012, 6:00:41 PM10/3/12

to

On Wed, 03 Oct 2012 14:18:09 -0700, Jim Thompson

It's what you "wound up with." It's stupid, so now you say it's "not
the real circuit." Of course, you won't reveal the "real" circuit...
it's proprietary.

Or more likely it doesn't exist. Or it's full of bugs, too.

John Larkin

unread,

Oct 3, 2012, 9:56:21 PM10/3/12

to

On Wed, 03 Oct 2012 11:49:26 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Wed, 03 Oct 2012 10:42:54 -0700, John Larkin
><jla...@highlandtechnology.com> wrote:
>
>[snip]
>>
>>If the design is for universal, CE-tested use, AC line voltage can go
>>to 264 RMS. That's 373 peak. In that case, the maximum fet dissipation
>>can be teased well over 1 watt; try it. That fet is rated 1.8 watts
>>max. If you sim one case, with nominal line voltage and typical Idss,
>>you are taking risks. Test lab time is expensive; product recalls and
>>fires are more expensive.
>>
>>Your sim seems to assume 240 line voltage.
>
>It's down-right amusing, YOU lecturing me on rigorous simulation. I
>often do 45 PVT corners.
>
>YOU, You post nothing but vague crap.
>
>Once I decide on a configuration I'll beat the crap out of it to make
>sure it's a valid design.
>
>Go sit in the corner and suck your thumb and contemplate how many
>other ways you can think of to pimp yourself >:-)
>
> ...Jim Thompson

Quote Jim:

"That's not the real circuit."

"Once I decide on a configuration..."

So, no good ideas yet? This is awfully simple; what's wrong?

--

John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

Jamie

unread,

Oct 3, 2012, 10:23:50 PM10/3/12

to

incandescent lamp in series, drops back down to low R afterwards, keeps
every one happy :)

Actually, a depletion mode mosfet inseries with a network can act as a
current limiter, give you low Ron values when not hitting the current
wall. That should make the heat radiator police happy.

Jamie

John Fields

unread,

Oct 4, 2012, 3:40:04 PM10/4/12

to

On Wed, 03 Oct 2012 14:55:09 -0700, John Larkin

---
In this instance, since you identified the input as "AC LINE" and the
thread is about mains driven current limited supplies, your
low-voltage driven doublers are irrelevant.

Also, the cleanliness of the source has very little to do with what
will happen when the mains gets switched into the load at different
angles.

--
JF

John Larkin

unread,

Oct 4, 2012, 4:14:50 PM10/4/12

to

On Thu, 04 Oct 2012 14:40:04 -0500, John Fields

All you do is whine.

Hey, the Blue Angels are buzzing the building. I'm headed for the
roof.

John Fields

unread,

Oct 5, 2012, 1:21:30 PM10/5/12

to

On Thu, 04 Oct 2012 13:14:50 -0700, John Larkin

---
All you do is run.

--
JF

Jamie

unread,

Oct 5, 2012, 7:14:25 PM10/5/12

to

Could also be signs of boredism?

Jamie

John Fields

unread,

Oct 5, 2012, 7:07:01 PM10/5/12

to

---
In response to any of _your_ posts, more than likely.

--
JF

John Fields

unread,

Oct 6, 2012, 5:33:45 PM10/6/12

to

---
--
JF

Cydrome Leader

unread,

Nov 23, 2012, 6:59:56 PM11/23/12

to

In sci.electronics.design Tom Biasi <tomb...@optonline.net> wrote:

> On 9/27/2012 3:44 PM, Jim Thompson wrote:
>> AC Cap Dropper DC Power Supply
>>
>> Anyone know of a clever way to regulate other than the typical
>> brute-force zener clamp?
>>
>> ...Jim Thompson
>>
>
>
>

> A long,long time ago in a place not so far away I used a transformer
> made by Sola that had a matched resonant capacitor.

ferroresonant transformer- they're peculiar beasts.

John Fields

unread,

Nov 23, 2012, 7:17:23 PM11/23/12

to

---
Ferroresonant?
--
JF

John Larkin

unread,

Nov 23, 2012, 7:39:54 PM11/23/12

to

Ferroresonant!

Cydrome Leader

unread,

Nov 23, 2012, 8:58:59 PM11/23/12

to

In sci.electronics.design John Larkin <jjla...@highnotlandthistechnologypart.com> wrote:
> On 1 Oct 2012 06:00:24 GMT, Jasen Betts <ja...@xnet.co.nz> wrote:
>
>>On 2012-09-30, John Larkin <jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>

>>> The series current-limiting cap dissipates no power, so it can be
>>> shorted by a low voltage switch. If it drives, say, the input of a

>>> bridge rectifier or a 2-diode restore thing, short the input of that.

>>> It becomes a bang-bang regulator. If the controller is to be a custom
>>> IC, a modest amount of complexity is free, so some intelligent
>>> zero-crossing thing would be appropriate. But just dumb bang-bang
>>> ought to work.
>>>
>>>

>>> This is one variation:
>>>
>>> https://dl.dropbox.com/u/53724080/Circuits/C-drop_regulator.jpg
>>
>>inrush current will destroy it.
>
> As I mentioned, and you snipped, people often include a series
> resistor to limit transient currents.
>

> C-limited supplies are commonly used for things like LED night-lights.

> It does take good engineering to do them right.

Not sure anybody cares, but the P3 killawatt meter uses cap shunter power
supply. Those thigs have no memory, so if you lose power you lose all your
logged data.

I figured, easy, I'll toss a supercap in there, no big deal, and who cares
if the display stays on.

Of course that never worked as the current from that power supply was
close to nothing and unable to charge the cap in the first place. Even
being plugged in for days didn't help as the leakage probably exceeded
what the watt meter itself used.

amdx

unread,

Nov 23, 2012, 9:37:37 PM11/23/12

to

On 9/27/2012 5:22 PM, Tom Biasi wrote:
> On 9/27/2012 3:44 PM, Jim Thompson wrote:
>> AC Cap Dropper DC Power Supply
>>
>> Anyone know of a clever way to regulate other than the typical
>> brute-force zener clamp?
>>
>> ...Jim Thompson
>>
>
>
>
> A long,long time ago in a place not so far away I used a transformer
> made by Sola that had a matched resonant capacitor.
>

> Tom

Years ago at a hamfest booth, I had a vendor begging me to take one
off his table. It weighed about 50 lbs, he was down to $9. It was
closing time. I didn't get it. It would still be in my storage.
Mikek

John Fields

unread,

Nov 24, 2012, 4:51:36 PM11/24/12

to

Ferroresonant.

--
JF

John Fields

unread,

Nov 24, 2012, 5:25:25 PM11/24/12

to

On Fri, 05 Oct 2012 12:21:30 -0500, John Fields

---
No timely reply?

Could it be that, as usual, you dodge the issue when you finally wake
up and find yourself with your foot in your mouth?

I think so.

Post a schematic to prove me wrong instead of your incessant blather.

--
JF

rickman

unread,

Nov 24, 2012, 12:35:55 AM11/24/12

to

On 10/3/2012 9:56 PM, John Larkin wrote:
> On Wed, 03 Oct 2012 11:49:26 -0700, Jim Thompson
>>

>> Go sit in the corner and suck your thumb and contemplate how many
>> other ways you can think of to pimp yourself>:-)
>>
>> ...Jim Thompson
>
> Quote Jim:
>
> "That's not the real circuit."
>
> "Once I decide on a configuration..."
>
> So, no good ideas yet? This is awfully simple; what's wrong?

I swear to god I would never do business with either of you two. You
both act like 12 year olds and right here in full public view.

Simply amazing...

Rick

John Larkin

unread,

Nov 26, 2012, 5:17:17 PM11/26/12

to

On Sat, 24 Nov 2012 16:25:25 -0600, John Fields

I suspect that JT never got a c-dropper circuit that works. His first
two tries were duds.

He's not very good once he gets off-chip.

--

John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

John Fields

unread,

Nov 28, 2012, 5:17:10 PM11/28/12

to

On Mon, 26 Nov 2012 14:17:17 -0800, John Larkin

---
Methinks if push came to shove he'd make inroads into your world which
you couldn't possibly make into his.

But that's really neither here nor there, since what's being discussed
is, ostensibly, your gobbledygook and your niggardly refusal to take
responsibility for your errors while trying to get off the hook by
damning others' as being worse than yours.

--
JF

John Larkin

unread,

Nov 28, 2012, 6:09:30 PM11/28/12

to

On Wed, 28 Nov 2012 16:17:10 -0600, John Fields

Well, I don't design chips. But, from what I've seen of his off-chip
design, I'm not very worried.

>
>But that's really neither here nor there, since what's being discussed
>is, ostensibly, your gobbledygook and your niggardly refusal to take
>responsibility for your errors while trying to get off the hook by
>damning others' as being worse than yours.

What you call "errors" are mostly philosophical word play. I design
electronics.

--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com

http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom laser drivers and controllers

Photonics and fiberoptic TTL data links

John Fields

unread,

Nov 28, 2012, 6:42:57 PM11/28/12

to

On Wed, 28 Nov 2012 15:09:30 -0800, John Larkin
<jla...@highlandtechnology.com> wrote:

>On Wed, 28 Nov 2012 16:17:10 -0600, John Fields
><jfi...@austininstruments.com> wrote:
>
>>On Mon, 26 Nov 2012 14:17:17 -0800, John Larkin
>><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>

>>>I suspect that JT never got a c-dropper circuit that works. His first
>>>two tries were duds.
>>>
>>>He's not very good once he gets off-chip.
>>
>>---
>>Methinks if push came to shove he'd make inroads into your world which
>>you couldn't possibly make into his.
>
>Well, I don't design chips. But, from what I've seen of his off-chip
>design, I'm not very worried.

---
I don't think he's interested in your turf, but, since you don't know
how to design chips and he knows how to design circuits, that puts you
at a loss.
---

>>But that's really neither here nor there, since what's being discussed
>>is, ostensibly, your gobbledygook and your niggardly refusal to take
>>responsibility for your errors while trying to get off the hook by
>>damning others' as being worse than yours.
>
>What you call "errors" are mostly philosophical word play.

---
Hardly.

I've called you to task, defined the parameters to which you refuse to
respond, and asked you to explain the inconsistencies in your
rhetoric, and yet you respond with silly dodges like:

---
I design electronics.
---

You don't, really.

All you do is take what's readily available and assemble it into
packages which you sell.

--
JF

John Larkin

unread,

Nov 28, 2012, 7:06:53 PM11/28/12

to

On Wed, 28 Nov 2012 17:42:57 -0600, John Fields

<jfi...@austininstruments.com> wrote:

>On Wed, 28 Nov 2012 15:09:30 -0800, John Larkin
><jla...@highlandtechnology.com> wrote:
>
>>On Wed, 28 Nov 2012 16:17:10 -0600, John Fields
>><jfi...@austininstruments.com> wrote:
>>
>>>On Mon, 26 Nov 2012 14:17:17 -0800, John Larkin
>>><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>>
>
>
>>>>I suspect that JT never got a c-dropper circuit that works. His first
>>>>two tries were duds.
>>>>
>>>>He's not very good once he gets off-chip.
>>>
>>>---
>>>Methinks if push came to shove he'd make inroads into your world which
>>>you couldn't possibly make into his.
>>
>>Well, I don't design chips. But, from what I've seen of his off-chip
>>design, I'm not very worried.
>
>---
>I don't think he's interested in your turf, but, since you don't know
>how to design chips and he knows how to design circuits, that puts you
>at a loss.

I'm having fun, working with interesting projects and people and
making a living. I don't feel any loss. Actually, being confined to
on-chip design, mostly working alone, simulating for weeks at a
stretch, would bore me to death.

>---
>
>>>But that's really neither here nor there, since what's being discussed
>>>is, ostensibly, your gobbledygook and your niggardly refusal to take
>>>responsibility for your errors while trying to get off the hook by
>>>damning others' as being worse than yours.
>>
>>What you call "errors" are mostly philosophical word play.
>
>---
>Hardly.
>
>I've called you to task, defined the parameters to which you refuse to
>respond, and asked you to explain the inconsistencies in your
>rhetoric, and yet you respond with silly dodges like:
>
>---
>I design electronics.
>---
>
>You don't, really.
>
>All you do is take what's readily available and assemble it into
>packages which you sell.

That's what electronic design is, putting parts and code together to
perform functions that people want. You could trivialize all novelists
that way... they just take words from dictionaries and string them
together. Or musicians... they just rearrange the same old notes.

John Fields

unread,

Nov 28, 2012, 7:29:53 PM11/28/12

to

On Wed, 28 Nov 2012 16:06:53 -0800, John Larkin

---
But when the string of words betrays the author or the string of notes
engenders cacophony, we witness your defense of your spew - your being
neither an author or a musician - as irrelevant.

--
JF

Jim Thompson

unread,

Nov 28, 2012, 7:32:10 PM11/28/12

to

On Wed, 28 Nov 2012 17:42:57 -0600, John Fields

I went back to the depletion mode FET approach. The cap dropper
scheme works only with +/- AC swings, not with schemes that are
rectified/one-sided/no-pull-down.

I do have cap dropper designs in almost all "American made" clothes
washing machines ;-)

The depletion mode FET, and nice swap-over when bootstrap comes up, is
working perfectly and is in MASS production in China.

I posted this result ages ago... like ~6 weeks back. Why is Larkin
still whining about it? Avoiding put up or shut up ?:-)

John Fields

unread,

Nov 28, 2012, 7:51:20 PM11/28/12

to

---
Indeed, but he'll always avoid either by not posting salient data
proving his position viable, or by muddying the waters.

He's made claims of designing cap-dropping power supplies, yet we see
nothing beyond his claims.

--
JF

John Larkin

unread,

Nov 28, 2012, 8:55:46 PM11/28/12

to

On Wed, 28 Nov 2012 18:51:20 -0600, John Fields

I pointed that out early in the game.

>>
>>I do have cap dropper designs in almost all "American made" clothes
>>washing machines ;-)
>>
>>The depletion mode FET, and nice swap-over when bootstrap comes up, is
>>working perfectly and is in MASS production in China.
>>
>>I posted this result ages ago... like ~6 weeks back. Why is Larkin
>>still whining about it? Avoiding put up or shut up ?:-)
>>
>> ...Jim Thompson
>---
>Indeed, but he'll always avoid either by not posting salient data
>proving his position viable, or by muddying the waters.
>
>He's made claims of designing cap-dropping power supplies, yet we see
>nothing beyond his claims.

I recall JT posting a depletion-fet circuit, then a triac thing, both
of which had problems. Was a third circuit posted?

Michael A. Terrell

unread,

Nov 29, 2012, 9:01:39 PM11/29/12

to

legg wrote:
>
> Who's on first.

<http://archive.org/download/otr_abbottandcostello/440606_Whos_On_First.mp3>

Jim Thompson

unread,

Nov 29, 2012, 10:10:06 PM11/29/12

to

One of my all time favorites!

My NOT favorite: "Abbott and Costello Meet Frankenstein"... not the
movie to see when you're a little kid and have to walk back thru the
woods, next to the State Asylum, at night.

I kid you not :-(

Michael A. Terrell

unread,

Nov 30, 2012, 2:19:31 PM11/30/12

to

Jim Thompson wrote:
>
> On Thu, 29 Nov 2012 21:01:39 -0500, "Michael A. Terrell"

> ?mike.t...@earthlink.net? wrote:
>
> ?
> ?legg wrote:
> ??
> ?? Who's on first.
> ?
> ??http://archive.org/download/otr_abbottandcostello/440606_Whos_On_First.mp3?

>
> One of my all time favorites!
>
> My NOT favorite: "Abbott and Costello Meet Frankenstein"... not the
> movie to see when you're a little kid and have to walk back thru the
> woods, next to the State Asylum, at night.
>
> I kid you not :-(

Then you don't want click this link.

<http://archive.org/download/otr_abbottandcostello/440113_VisitToASanitarium.mp3>

Jim Thompson

unread,

Nov 30, 2012, 2:25:00 PM11/30/12

to

I can cope now, but fathom the situation when you're maybe 8 years
old.

(Back in the never-to-return past when it was safe to let your kids
walk thru the woods to the theater... now there are Democrats out
there :-)

Michael A. Terrell

unread,

Nov 30, 2012, 5:16:10 PM11/30/12

to

Jim Thompson wrote:
>
> I can cope now, but fathom the situation when you're maybe 8 years
> old.

You can download the movie from several sites for free. It's likely
to be found on Youtube, as well.

Yes, it really bothers some people, but some just laughed at those
movies. No big deal on who was who. Very few ever bothered me, and that
movie came out before I was born. I think I saw it on the local TV
station when I was a teenager. It ran with movies like 'The Claw!!!'
;-)

OTOH, I cultivated the belief in kids at a local school that I was a
dangers & crazy man. They vandalized a lot of houses & stole from my
neighbors but you couldn't get a one of them to walk through my yard for
anything. If i stood on my front porch when school let out, the kids
would walk n extra four blocks, instead of past my house. :)

> (Back in the never-to-return past when it was safe to let your kids
> walk thru the woods to the theater... now there are Democrats out
> there :-)

Most are toothless & in straight jackets. The worst most can do is to
drool on some poor kid! ;-)

tuinkabouter

unread,

Nov 30, 2012, 5:40:57 PM11/30/12

to

On 11/30/2012 8:25 PM, Jim Thompson wrote:
> On Fri, 30 Nov 2012 14:19:31 -0500, "Michael A. Terrell"
> <mike.t...@earthlink.net> wrote:
>
>>
>> Jim Thompson wrote:
>>>
>>> On Thu, 29 Nov 2012 21:01:39 -0500, "Michael A. Terrell"
>>> ?mike.t...@earthlink.net? wrote:
>>>
>>> ?
>>> ?legg wrote:
>>> ??
>>> ?? Who's on first.
>>> ?
>>> ??http://archive.org/download/otr_abbottandcostello/440606_Whos_On_First.mp3?
>>>
>>> One of my all time favorites!
>>>
>>> My NOT favorite: "Abbott and Costello Meet Frankenstein"... not the
>>> movie to see when you're a little kid and have to walk back thru the
>>> woods, next to the State Asylum, at night.
>>>
>>> I kid you not :-(
>>
>>
>> Then you don't want click this link.
>>
>> <http://archive.org/download/otr_abbottandcostello/440113_VisitToASanitarium.mp3>
>
> I can cope now, but fathom the situation when you're maybe 8 years
> old.
>
> (Back in the never-to-return past when it was safe to let your kids
> walk thru the woods to the theater... now there are Democrats out
> there :-)

Yes, God must really hate republicans.

Jim Thompson

unread,

Nov 30, 2012, 7:01:44 PM11/30/12

to

I always liked "The Thing" >:-}

Jim Thompson

unread,

Nov 30, 2012, 7:02:44 PM11/30/12

to

And the Democrats have reading comprehension problems >:-}

John Fields

unread,

Nov 30, 2012, 7:04:54 PM11/30/12

to

On Wed, 28 Nov 2012 17:55:46 -0800, John Larkin

---
Not as far as I can tell but, it's not about JT, it's about you and
your need to defame the character of your detractors.

--
JF

Jim Thompson

unread,

Nov 30, 2012, 7:17:56 PM11/30/12

to

On Fri, 30 Nov 2012 18:04:54 -0600, John Fields

All the first variations had a cap-dropper in them, which doesn't work
without a discharge path. TRIAC works super on an AC-input cap
dropper... really low dissipation. Depletion mode FET works on "DC"
quite nicely, and is in production... shipping just a fast as they can
knock them out.

Message has been deleted