> On 11/15/2011 10:24 PM, josephkk wrote:
>
>> On Tue, 15 Nov 2011 04:47:41 -0500, "Michael A. Terrell"
>> <mike.terrell@earthlink.net> wrote:
>>
>>>
>>> John Larkin wrote:
>>>
>>>>
>>>> Jamie wrote:
>>>>
>>>>> how do you figure that?
>>>>
>>>>
>>>> Just look at it. It has a hangup state, with the transformer CT low
>>>> and the flipflop clock input high. It would take luck at powerup for
>>>> it to not get into that state.
>>
>>
>> I don't think so. It would take little circuitry to guarantee startup
>> conditions for the J-K or the D FF configuration. Especially if set or
>> reset inputs are available. Play with it a bit.
>
>
> That circuit is not a good one. One power supply glitch, or somebody
> nearby with a cell phone, or a small ESD event, and the whole thing goes
> up in smoke. It's far easier to design a reliable circuit, i.e. one
> that will recover from such things, than it is to bandage a bad one.
> It's not as though there's a shortage of good ways to do this.
>
> Cheers
>
> Phil Hobbs
>
>
>
It seems like the thread is getting a little hacked up..
I'll say it one more time, that isn't the exact circuit I used! That
was a conception circuit to show the use of the /Q and Q outputs.
I used a spare on the board. The Feed back from the CT was used to
shape the signal a little to remove noise on the corners. The pull up
was from a already operating signal in the circuit.
That was a last minute hack I did because I needed a small isolated
source and what better place to get it, from a un-used FF as a bridge
type driver.
But as it turns out, I needed the sense R and cap to cause a little
delay on the transitions to help clean up the signal.
As far as self oscillating ? I've done that too, but not in that
configuration.
Jamie
Reply by Phil Hobbs●November 15, 20112011-11-15
On 11/15/2011 10:24 PM, josephkk wrote:
> On Tue, 15 Nov 2011 04:47:41 -0500, "Michael A. Terrell"
> <mike.terrell@earthlink.net> wrote:
>
>>
>> John Larkin wrote:
>>>
>>> Jamie wrote:
>>>
>>>> how do you figure that?
>>>
>>> Just look at it. It has a hangup state, with the transformer CT low
>>> and the flipflop clock input high. It would take luck at powerup for
>>> it to not get into that state.
>
> I don't think so. It would take little circuitry to guarantee startup
> conditions for the J-K or the D FF configuration. Especially if set or
> reset inputs are available. Play with it a bit.
That circuit is not a good one. One power supply glitch, or somebody
nearby with a cell phone, or a small ESD event, and the whole thing goes
up in smoke. It's far easier to design a reliable circuit, i.e. one
that will recover from such things, than it is to bandage a bad one.
It's not as though there's a shortage of good ways to do this.
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
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
Reply by josephkk●November 15, 20112011-11-15
On Tue, 15 Nov 2011 04:47:41 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
>
>John Larkin wrote:
>>=20
>> Jamie wrote:
>>
>> >how do you figure that?
>>=20
>> Just look at it. It has a hangup state, with the transformer CT low
>> and the flipflop clock input high. It would take luck at powerup for
>> it to not get into that state.
I don't think so. It would take little circuitry to guarantee startup
conditions for the J-K or the D FF configuration. Especially if set or
reset inputs are available. Play with it a bit.
>>=20
>> It's like one of those hairball one-shot circuits that runs pulses
>> around in circles, started up at powerup somehow. If it ever messes up
>> once, it's dead.
>>=20
>> Something like a schmitt trigger gate oscillator feeding a transformer
>> would be safe.
>
>
> Maynard A Philbrook JR, AKA 'Jamie' doesn't know Schmitt!
Reply by Michael A. Terrell●November 15, 20112011-11-15
John Larkin wrote:
>
> Jamie wrote:
>
> >how do you figure that?
>
> Just look at it. It has a hangup state, with the transformer CT low
> and the flipflop clock input high. It would take luck at powerup for
> it to not get into that state.
>
> It's like one of those hairball one-shot circuits that runs pulses
> around in circles, started up at powerup somehow. If it ever messes up
> once, it's dead.
>
> Something like a schmitt trigger gate oscillator feeding a transformer
> would be safe.
Maynard A Philbrook JR, AKA 'Jamie' doesn't know Schmitt!
--
You can't have a sense of humor, if you have no sense.
Reply by Jamie●November 14, 20112011-11-14
John Larkin wrote:
> On Mon, 14 Nov 2011 20:05:49 -0500, Jamie
> <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>
>
>>John Larkin wrote:
>>
>>
>>>On Sat, 12 Nov 2011 21:45:25 -0500, Jamie
>>><jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>>>
>>>
>>>
>>>>John Larkin wrote:
>>>>
>>>>
>>>>
>>>>>On Sat, 12 Nov 2011 16:27:49 -0800, Joerg <invalid@invalid.invalid>
>>>>>wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>John Larkin wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>On Sat, 12 Nov 2011 15:05:57 -0800, Joerg <invalid@invalid.invalid>
>>>>>>>wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>John Larkin wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>On Sat, 12 Nov 2011 21:28:53 GMT, Mike <spam@me.not> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>Joerg <invalid@invalid.invalid> wrote:
>>>>>>>>
>>>>>>>>[...]
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>>The energy that goes through the other diode to ground is simply lost. Is
>>>>>>>>>>this lost energy accounted for in the efficiency calculations?
>>>>>>>>>>
>>>>>>>>>>I noticed playing with Larkin's amazing capacitor bypass patent that a
>>>>>>>>>>little miller on the mosfet dramatically changed the conditions at
>>>>>>>>>>turnoff. It had a huge effect on all the waveforms. I told Larkin he
>>>>>>>>>>would not like it.
>>>>>>>>>
>>>>>>>>>I don't like Miller capacitance? I never knew that.
>>>>>>>>>
>>>>>>>>
>>>>>>>>No, that was Gus Portokalos.
>>>>>>>
>>>>>>>Great movie.
>>>>>>>
>>>>>>
>>>>>>Yes, I could probably watch it five more times and not get bored.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>He didn't like the Millers, at least not
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>until after Toula and Ian were married.
>>>>>>>
>>>>>>>Miller Lite is ok if you're hot and thirsty and just need something
>>>>>>>wet to drink.
>>>>>>>
>>>>>>
>>>>>>Yuck ... Gordon Biersch isn't too far from you guys and there you can
>>>>>>get some real stuff.
>>>>>
>>>>>
>>>>>I don't like the GB stuff. Too hoppy for my taste. Lately we've been
>>>>>drinking Widmer and Stella and Purple Haze, abd Harp, translucent
>>>>>stuff like that. I don't trust liquids that I can't see through.
>>>>>
>>>>>My wife does drink Guinness. Can't imagine why.
>>>>>
>>>>>Some of the brit "pub" beers are OK, like Boddington and Speckled Hen.
>>>>>Both have the nitrogen thingie inside.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>>>>When I use 270 ohm gate resistors in by little converter, I get really
>>>>>>>>>nice smooth trapezoidal edges. What's not to like?
>>>>>>>>>
>>>>>>>>
>>>>>>>>It makes heat which you probably can't use on that board. And it isn't
>>>>>>>>green to do that :-)
>>>>>>>
>>>>>>>I'm running about 75% efficiency, 24 VDC in, 9 volts out at 4 watts.
>>>>>>>The fets are cold. I'm losing about a volt in the bridge rectifiers,
>>>>>>>over 10% right there. There's loss in the transformer, too. Not bad,
>>>>>>>overall.
>>>>>>>
>>>>>>
>>>>>>I believe you are running a DRQ127 330uH at around 100kHz. That's a bit
>>>>>>tight, they are only around 100V-usec. So some saturation and core
>>>>>>losses there.
>>>>>
>>>>>
>>>>>150 KHz, and the drive into the transformer is 24 volts p-p. Lots of
>>>>>margin.
>>>>>
>>>>>John
>>>>>
>>>>
>>>>years ago I did a hack. Needed an isolated low current reference source,
>>>>so there was this spare TTL FF in the circuit not being used.
>>>>
>>>>I did something like this with a couple of minor things added.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> +-----------+. ,-
>>>> PULL ^ .--o--. | I(SENSE) )|(
>>>> ___ -|J S Q+--+ ___ )|(
>>>> -|___|+--+----+|> | -|___|-+--+. ,-
>>>> | -|K R Q+--+ | )|(
>>>> | '--o--' | | )|(
>>>> | +--------|-+-' '-
>>>> | |
>>>> --- |
>>>> PULSE CAP --- |
>>>> + |
>>>> +--+--------------------+
>>>>(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
>>>>
>>>>I placed all the components I needed on a daughter board and stuck it
>>>>in there vertically attaching it to the FF that was in the circuit already.
>>>>
>>>>Of course I have a full wave rectifier on the other side with cap.
>>>>
>>>>
>>>>Jamie
>>>
>>>
>>>Yikes! That circuit has two states, working and not-working.
>>>
>>>John
>>>
>>
>>how do you figure that?
>
>
> Just look at it. It has a hangup state, with the transformer CT low
> and the flipflop clock input high. It would take luck at powerup for
> it to not get into that state.
>
> It's like one of those hairball one-shot circuits that runs pulses
> around in circles, started up at powerup somehow. If it ever messes up
> once, it's dead.
>
> Something like a schmitt trigger gate oscillator feeding a transformer
> would be safe.
>
> John
>
>
I don't know what to tell you john except that it has worked for me with
no problems. What else can I say?
Jamie
Reply by John Larkin●November 14, 20112011-11-14
On Mon, 14 Nov 2011 20:05:49 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>John Larkin wrote:
>
>> On Sat, 12 Nov 2011 21:45:25 -0500, Jamie
>> <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>>
>>
>>>John Larkin wrote:
>>>
>>>
>>>>On Sat, 12 Nov 2011 16:27:49 -0800, Joerg <invalid@invalid.invalid>
>>>>wrote:
>>>>
>>>>
>>>>
>>>>>John Larkin wrote:
>>>>>
>>>>>
>>>>>>On Sat, 12 Nov 2011 15:05:57 -0800, Joerg <invalid@invalid.invalid>
>>>>>>wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>John Larkin wrote:
>>>>>>>
>>>>>>>
>>>>>>>>On Sat, 12 Nov 2011 21:28:53 GMT, Mike <spam@me.not> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>Joerg <invalid@invalid.invalid> wrote:
>>>>>>>
>>>>>>>[...]
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>>The energy that goes through the other diode to ground is simply lost. Is
>>>>>>>>>this lost energy accounted for in the efficiency calculations?
>>>>>>>>>
>>>>>>>>>I noticed playing with Larkin's amazing capacitor bypass patent that a
>>>>>>>>>little miller on the mosfet dramatically changed the conditions at
>>>>>>>>>turnoff. It had a huge effect on all the waveforms. I told Larkin he
>>>>>>>>>would not like it.
>>>>>>>>
>>>>>>>>I don't like Miller capacitance? I never knew that.
>>>>>>>>
>>>>>>>
>>>>>>>No, that was Gus Portokalos.
>>>>>>
>>>>>>Great movie.
>>>>>>
>>>>>
>>>>>Yes, I could probably watch it five more times and not get bored.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>He didn't like the Millers, at least not
>>>>>>
>>>>>>
>>>>>>>until after Toula and Ian were married.
>>>>>>
>>>>>>Miller Lite is ok if you're hot and thirsty and just need something
>>>>>>wet to drink.
>>>>>>
>>>>>
>>>>>Yuck ... Gordon Biersch isn't too far from you guys and there you can
>>>>>get some real stuff.
>>>>
>>>>
>>>>I don't like the GB stuff. Too hoppy for my taste. Lately we've been
>>>>drinking Widmer and Stella and Purple Haze, abd Harp, translucent
>>>>stuff like that. I don't trust liquids that I can't see through.
>>>>
>>>>My wife does drink Guinness. Can't imagine why.
>>>>
>>>>Some of the brit "pub" beers are OK, like Boddington and Speckled Hen.
>>>>Both have the nitrogen thingie inside.
>>>>
>>>>
>>>>
>>>>>>>>When I use 270 ohm gate resistors in by little converter, I get really
>>>>>>>>nice smooth trapezoidal edges. What's not to like?
>>>>>>>>
>>>>>>>
>>>>>>>It makes heat which you probably can't use on that board. And it isn't
>>>>>>>green to do that :-)
>>>>>>
>>>>>>I'm running about 75% efficiency, 24 VDC in, 9 volts out at 4 watts.
>>>>>>The fets are cold. I'm losing about a volt in the bridge rectifiers,
>>>>>>over 10% right there. There's loss in the transformer, too. Not bad,
>>>>>>overall.
>>>>>>
>>>>>
>>>>>I believe you are running a DRQ127 330uH at around 100kHz. That's a bit
>>>>>tight, they are only around 100V-usec. So some saturation and core
>>>>>losses there.
>>>>
>>>>
>>>>150 KHz, and the drive into the transformer is 24 volts p-p. Lots of
>>>>margin.
>>>>
>>>>John
>>>>
>>>
>>>years ago I did a hack. Needed an isolated low current reference source,
>>>so there was this spare TTL FF in the circuit not being used.
>>>
>>> I did something like this with a couple of minor things added.
>>>
>>>
>>>
>>>
>>>
>>> +-----------+. ,-
>>> PULL ^ .--o--. | I(SENSE) )|(
>>> ___ -|J S Q+--+ ___ )|(
>>> -|___|+--+----+|> | -|___|-+--+. ,-
>>> | -|K R Q+--+ | )|(
>>> | '--o--' | | )|(
>>> | +--------|-+-' '-
>>> | |
>>> --- |
>>> PULSE CAP --- |
>>> + |
>>> +--+--------------------+
>>>(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
>>>
>>>I placed all the components I needed on a daughter board and stuck it
>>>in there vertically attaching it to the FF that was in the circuit already.
>>>
>>> Of course I have a full wave rectifier on the other side with cap.
>>>
>>>
>>>Jamie
>>
>>
>> Yikes! That circuit has two states, working and not-working.
>>
>> John
>>
>how do you figure that?
Just look at it. It has a hangup state, with the transformer CT low
and the flipflop clock input high. It would take luck at powerup for
it to not get into that state.
It's like one of those hairball one-shot circuits that runs pulses
around in circles, started up at powerup somehow. If it ever messes up
once, it's dead.
Something like a schmitt trigger gate oscillator feeding a transformer
would be safe.
John
Reply by Jamie●November 14, 20112011-11-14
John Larkin wrote:
> On Sat, 12 Nov 2011 21:45:25 -0500, Jamie
> <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>
>
>>John Larkin wrote:
>>
>>
>>>On Sat, 12 Nov 2011 16:27:49 -0800, Joerg <invalid@invalid.invalid>
>>>wrote:
>>>
>>>
>>>
>>>>John Larkin wrote:
>>>>
>>>>
>>>>>On Sat, 12 Nov 2011 15:05:57 -0800, Joerg <invalid@invalid.invalid>
>>>>>wrote:
>>>>>
>>>>>
>>>>>
>>>>>>John Larkin wrote:
>>>>>>
>>>>>>
>>>>>>>On Sat, 12 Nov 2011 21:28:53 GMT, Mike <spam@me.not> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>Joerg <invalid@invalid.invalid> wrote:
>>>>>>
>>>>>>[...]
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>The energy that goes through the other diode to ground is simply lost. Is
>>>>>>>>this lost energy accounted for in the efficiency calculations?
>>>>>>>>
>>>>>>>>I noticed playing with Larkin's amazing capacitor bypass patent that a
>>>>>>>>little miller on the mosfet dramatically changed the conditions at
>>>>>>>>turnoff. It had a huge effect on all the waveforms. I told Larkin he
>>>>>>>>would not like it.
>>>>>>>
>>>>>>>I don't like Miller capacitance? I never knew that.
>>>>>>>
>>>>>>
>>>>>>No, that was Gus Portokalos.
>>>>>
>>>>>Great movie.
>>>>>
>>>>
>>>>Yes, I could probably watch it five more times and not get bored.
>>>>
>>>>
>>>>
>>>>
>>>>>He didn't like the Millers, at least not
>>>>>
>>>>>
>>>>>>until after Toula and Ian were married.
>>>>>
>>>>>Miller Lite is ok if you're hot and thirsty and just need something
>>>>>wet to drink.
>>>>>
>>>>
>>>>Yuck ... Gordon Biersch isn't too far from you guys and there you can
>>>>get some real stuff.
>>>
>>>
>>>I don't like the GB stuff. Too hoppy for my taste. Lately we've been
>>>drinking Widmer and Stella and Purple Haze, abd Harp, translucent
>>>stuff like that. I don't trust liquids that I can't see through.
>>>
>>>My wife does drink Guinness. Can't imagine why.
>>>
>>>Some of the brit "pub" beers are OK, like Boddington and Speckled Hen.
>>>Both have the nitrogen thingie inside.
>>>
>>>
>>>
>>>>>>>When I use 270 ohm gate resistors in by little converter, I get really
>>>>>>>nice smooth trapezoidal edges. What's not to like?
>>>>>>>
>>>>>>
>>>>>>It makes heat which you probably can't use on that board. And it isn't
>>>>>>green to do that :-)
>>>>>
>>>>>I'm running about 75% efficiency, 24 VDC in, 9 volts out at 4 watts.
>>>>>The fets are cold. I'm losing about a volt in the bridge rectifiers,
>>>>>over 10% right there. There's loss in the transformer, too. Not bad,
>>>>>overall.
>>>>>
>>>>
>>>>I believe you are running a DRQ127 330uH at around 100kHz. That's a bit
>>>>tight, they are only around 100V-usec. So some saturation and core
>>>>losses there.
>>>
>>>
>>>150 KHz, and the drive into the transformer is 24 volts p-p. Lots of
>>>margin.
>>>
>>>John
>>>
>>
>>years ago I did a hack. Needed an isolated low current reference source,
>>so there was this spare TTL FF in the circuit not being used.
>>
>> I did something like this with a couple of minor things added.
>>
>>
>>
>>
>>
>> +-----------+. ,-
>> PULL ^ .--o--. | I(SENSE) )|(
>> ___ -|J S Q+--+ ___ )|(
>> -|___|+--+----+|> | -|___|-+--+. ,-
>> | -|K R Q+--+ | )|(
>> | '--o--' | | )|(
>> | +--------|-+-' '-
>> | |
>> --- |
>> PULSE CAP --- |
>> + |
>> +--+--------------------+
>>(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
>>
>>I placed all the components I needed on a daughter board and stuck it
>>in there vertically attaching it to the FF that was in the circuit already.
>>
>> Of course I have a full wave rectifier on the other side with cap.
>>
>>
>>Jamie
>
>
> Yikes! That circuit has two states, working and not-working.
>
> John
>
how do you figure that?
Btw, that isn't the exact circuit that was in use but is the concept of
how it works.
THe sense R is connected to the (+) rail as with the pull up R, I just
didn't draw all of the circuit, I'd figure any one that knew something
would know that and fill in the obvious :)
When the primary saturates to the current point you need it'll drop
the voltage at the sense R and generate a pulse that flips /Q Q which
will then drive it the other way and start the cycle all over again.
(push pull)
It works fine for a low current isolated supply. I used a D-FF not a
master sleeve like above.. That was just something I picked from that
ASC program. And may of also used a transistor to drive the Clk input,
It's been a while..
Jamie
Reply by John Larkin●November 14, 20112011-11-14
On Sat, 12 Nov 2011 21:45:25 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>John Larkin wrote:
>
>> On Sat, 12 Nov 2011 16:27:49 -0800, Joerg <invalid@invalid.invalid>
>> wrote:
>>
>>
>>>John Larkin wrote:
>>>
>>>>On Sat, 12 Nov 2011 15:05:57 -0800, Joerg <invalid@invalid.invalid>
>>>>wrote:
>>>>
>>>>
>>>>>John Larkin wrote:
>>>>>
>>>>>>On Sat, 12 Nov 2011 21:28:53 GMT, Mike <spam@me.not> wrote:
>>>>>>
>>>>>>
>>>>>>>Joerg <invalid@invalid.invalid> wrote:
>>>>>
>>>>>[...]
>>>>>
>>>>>
>>>>>
>>>>>>>The energy that goes through the other diode to ground is simply lost. Is
>>>>>>>this lost energy accounted for in the efficiency calculations?
>>>>>>>
>>>>>>>I noticed playing with Larkin's amazing capacitor bypass patent that a
>>>>>>>little miller on the mosfet dramatically changed the conditions at
>>>>>>>turnoff. It had a huge effect on all the waveforms. I told Larkin he
>>>>>>>would not like it.
>>>>>>
>>>>>>I don't like Miller capacitance? I never knew that.
>>>>>>
>>>>>
>>>>>No, that was Gus Portokalos.
>>>>
>>>>Great movie.
>>>>
>>>
>>>Yes, I could probably watch it five more times and not get bored.
>>>
>>>
>>>
>>>> He didn't like the Millers, at least not
>>>>
>>>>>until after Toula and Ian were married.
>>>>
>>>>Miller Lite is ok if you're hot and thirsty and just need something
>>>>wet to drink.
>>>>
>>>
>>>Yuck ... Gordon Biersch isn't too far from you guys and there you can
>>>get some real stuff.
>>
>>
>> I don't like the GB stuff. Too hoppy for my taste. Lately we've been
>> drinking Widmer and Stella and Purple Haze, abd Harp, translucent
>> stuff like that. I don't trust liquids that I can't see through.
>>
>> My wife does drink Guinness. Can't imagine why.
>>
>> Some of the brit "pub" beers are OK, like Boddington and Speckled Hen.
>> Both have the nitrogen thingie inside.
>>
>>
>>>>>>When I use 270 ohm gate resistors in by little converter, I get really
>>>>>>nice smooth trapezoidal edges. What's not to like?
>>>>>>
>>>>>
>>>>>It makes heat which you probably can't use on that board. And it isn't
>>>>>green to do that :-)
>>>>
>>>>I'm running about 75% efficiency, 24 VDC in, 9 volts out at 4 watts.
>>>>The fets are cold. I'm losing about a volt in the bridge rectifiers,
>>>>over 10% right there. There's loss in the transformer, too. Not bad,
>>>>overall.
>>>>
>>>
>>>I believe you are running a DRQ127 330uH at around 100kHz. That's a bit
>>>tight, they are only around 100V-usec. So some saturation and core
>>>losses there.
>>
>>
>> 150 KHz, and the drive into the transformer is 24 volts p-p. Lots of
>> margin.
>>
>> John
>>
>years ago I did a hack. Needed an isolated low current reference source,
>so there was this spare TTL FF in the circuit not being used.
>
> I did something like this with a couple of minor things added.
>
>
>
>
>
> +-----------+. ,-
> PULL ^ .--o--. | I(SENSE) )|(
> ___ -|J S Q+--+ ___ )|(
> -|___|+--+----+|> | -|___|-+--+. ,-
> | -|K R Q+--+ | )|(
> | '--o--' | | )|(
> | +--------|-+-' '-
> | |
> --- |
> PULSE CAP --- |
> + |
> +--+--------------------+
>(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
>
>I placed all the components I needed on a daughter board and stuck it
>in there vertically attaching it to the FF that was in the circuit already.
>
> Of course I have a full wave rectifier on the other side with cap.
>
>
>Jamie
Yikes! That circuit has two states, working and not-working.
John
Reply by Jeroen Belleman●November 14, 20112011-11-14
Joerg wrote:
> dagmargoodboat@yahoo.com wrote:
>
> [...]
>
>> Making each figure of the article an individual .PDF needing
>> downloading maximizes the uselessness of getting it from EDN.
>>
>
> I have never understood why they do that. Someone higher up on the
> editorial board must have dozed off a long time ago :-)
>
Bah. They probably set their advertising tariffs by the number of
downloads. Common bean-counter tactics.
Jeroen Belleman
Reply by Joerg●November 13, 20112011-11-13
dagmargoodboat@yahoo.com wrote:
[...]
>
> Making each figure of the article an individual .PDF needing
> downloading maximizes the uselessness of getting it from EDN.
>
I have never understood why they do that. Someone higher up on the
editorial board must have dozed off a long time ago :-)
--
Regards, Joerg
http://www.analogconsultants.com/