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Need the topology for a current to current SMPS, not voltage to voltage SMPS

Started by RobertMacy October 16, 2013
In article <bcl843F3fq9U3@mid.individual.net>,
Joerg  <news@analogconsultants.com> wrote:

>I raise you one: I have a megacycle meter 8-) > >This one: > >http://www.ohio.edu/people/postr/bapix/Dip_59.htm
Ah, yes! Into every forest of test equipment, a little acorn (tube) must fall! This really is an excellent piece of "kit". A few years ago I did a comparison of my Model 59, a Heathkit dipper, and the dipper coil accessory set for an MFJ 269 impedance meter. The test fixture was a piece of Airdux coil, with an air variable capacitor soldered across the ends. Should have a nice high Q. The MFJ-and-probe combination was... well, saying "pathetic" and "an absolute waste of money and effort" is about right. In order to get any readable dip in the meter I had to shove the probe to within a small fraction of an inch of the Airdux coil. Talk about a measurement, affecting the thing to be measured :-( The Heathkit solid-state dipper did better. I could get a good reading by just barely bringing the coil to the center end of the Airdux... wouldn't have been much capacitive coupling to worry about. The Measurements 59 - wow. Nice sharp high-Q narrow dip with the coil about 2" away from the center of the Airdux. The best combination would probably be the 59 as a dipper, and the MJF in frequency-counter mode to give a more precise reading on the dip frequency, just as the article you pointed to suggests.
John S wrote:
> On 10/21/2013 10:57 AM, George Herold wrote: >> On Monday, October 21, 2013 11:14:10 AM UTC-4, John S wrote:
[...]
>>> >>> Yes, thank you, George. I saw it. But your image and your ASCII >>> drawing >>> >>> above do not agree. Your ASCII drawing is a standard buck without >>> an >>> >>> output filter capacitor. I agree with your ASCII (with, possibly, >>> the >>> >>> requirement for an output filter capacitor) for a scheme which >>> could work. >> >> Grin.. sure... the ascii is a current boost and the first dropbox >> scribble is a current buck. I'm not sure what you mean about the >> ascii drawing... It's being fed from a current source.. so how can >> it be a 'standard buck'. (The output is also a (DC) current.. so I >> can't really put a capacitor there.) > > I don't really care about the source. It's max voltage is specified at > 100V, no? It' max (and constant) current is specified at .05A, no? > > There is therefore a maximum power output capability of 5W. No? >
I think the easiest way for the large compliance range is a flyback that measures the input current and regulated to an output current of desired (or programmable) magnitude in relation to the measured input current. Then it's input voltage will automatically adjust to what is needed, without wasting anything other than the losses in the flyback. Of course, the 95% requirement pretty much mandates a recuperating winding so it'll be a custom transformer. No flaring off of the leakage inductance spikes in snubbers or zeners.
> It does not matter what topology you use, you cannot get more out than > you put in. Where am I wrong here? >
Washington "gets" about 50% more out than what comes in :-( [...] -- Regards, Joerg http://www.analogconsultants.com/
David Platt wrote:
> In article <bcl843F3fq9U3@mid.individual.net>, > Joerg <news@analogconsultants.com> wrote: > >> I raise you one: I have a megacycle meter 8-) >> >> This one: >> >> http://www.ohio.edu/people/postr/bapix/Dip_59.htm > > Ah, yes! Into every forest of test equipment, a little acorn (tube) > must fall! > > This really is an excellent piece of "kit". A few years ago I did a > comparison of my Model 59, a Heathkit dipper, and the dipper coil > accessory set for an MFJ 269 impedance meter. > > The test fixture was a piece of Airdux coil, with an air variable > capacitor soldered across the ends. Should have a nice high Q. > > The MFJ-and-probe combination was... well, saying "pathetic" and "an > absolute waste of money and effort" is about right. In order to get > any readable dip in the meter I had to shove the probe to within a > small fraction of an inch of the Airdux coil. Talk about a > measurement, affecting the thing to be measured :-( > > The Heathkit solid-state dipper did better. I could get a good > reading by just barely bringing the coil to the center end of the > Airdux... wouldn't have been much capacitive coupling to worry about. > > The Measurements 59 - wow. Nice sharp high-Q narrow dip with the > coil about 2" away from the center of the Airdux. >
In them days people still knew how it's done. I bet it is possible to copy a Model 59 using semiconductors, such as dual-gate FETs. But there is no market. Most kids these days don't have a clue what a dipmeter is. In fact, whenever I showed up with my Heathkit 1250 the only folks who knew what that weird thang was were ham radio operators well past the age of 50.
> The best combination would probably be the 59 as a dipper, and the MJF > in frequency-counter mode to give a more precise reading on the dip > frequency, just as the article you pointed to suggests. >
Nowadays you can easily achieve that precision: Use the Model 59 and run the spectrum analyzer in parallel, using a loop antenna underneath your work bench. Make it snap to the strongest signal. BTDT. Now, about changing the display of the spectrum analyzer to megacycles ... -- Regards, Joerg http://www.analogconsultants.com/
On 10/21/2013 02:34 PM, RobertMacy wrote:
> On Mon, 21 Oct 2013 10:55:11 -0700, Joerg <invalid@invalid.invalid> wrote: > >>> ...snip... >> I raise you one: I have a megacycle meter 8-) >> >> This one: >> >> http://www.ohio.edu/people/postr/bapix/Dip_59.htm >> > > That's too bad you won't be able to use it, since it measures megacycles > and megacycles no longer exist. Unless you can find some equipment that > produces megacycles, like...perhaps I can help, I have an original pair > of WWII walkietalkies! > > You have NO idea how long it took me to stop saying > megacycles/kilocycles and start saying megaHertz/kiloHertz.
I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is 100 fA FS). Not to be too pico, er, picky. 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
Phil Hobbs wrote:
> On 10/21/2013 02:34 PM, RobertMacy wrote: >> On Mon, 21 Oct 2013 10:55:11 -0700, Joerg <invalid@invalid.invalid> >> wrote: >> >>>> ...snip... >>> I raise you one: I have a megacycle meter 8-) >>> >>> This one: >>> >>> http://www.ohio.edu/people/postr/bapix/Dip_59.htm >>> >> >> That's too bad you won't be able to use it, since it measures megacycles >> and megacycles no longer exist. Unless you can find some equipment that >> produces megacycles, like...perhaps I can help, I have an original pair >> of WWII walkietalkies! >> >> You have NO idea how long it took me to stop saying >> megacycles/kilocycles and start saying megaHertz/kiloHertz. > > I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is > 100 fA FS). Not to be too pico, er, picky. >
I can raise you one more. Here is an "entertainment system" we have at the entrance: http://www.electricstuff.co.uk/3nfset.jpg It essentially contains the first IC in the world. The tube contains three sections, four resistors and two capacitors (it's all inside the glass). IIRC my grandpa bought it in 1927. He was always the early adopter when it came to technology. -- Regards, Joerg http://www.analogconsultants.com/
On 10/21/2013 03:44 PM, Joerg wrote:
> Phil Hobbs wrote: >> On 10/21/2013 02:34 PM, RobertMacy wrote: >>> On Mon, 21 Oct 2013 10:55:11 -0700, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>>> ...snip... >>>> I raise you one: I have a megacycle meter 8-) >>>> >>>> This one: >>>> >>>> http://www.ohio.edu/people/postr/bapix/Dip_59.htm >>>> >>> >>> That's too bad you won't be able to use it, since it measures megacycles >>> and megacycles no longer exist. Unless you can find some equipment that >>> produces megacycles, like...perhaps I can help, I have an original pair >>> of WWII walkietalkies! >>> >>> You have NO idea how long it took me to stop saying >>> megacycles/kilocycles and start saying megaHertz/kiloHertz. >> >> I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is >> 100 fA FS). Not to be too pico, er, picky. >> > > I can raise you one more. Here is an "entertainment system" we have at > the entrance: > > http://www.electricstuff.co.uk/3nfset.jpg > > It essentially contains the first IC in the world. The tube contains > three sections, four resistors and two capacitors (it's all inside the > glass). IIRC my grandpa bought it in 1927. He was always the early > adopter when it came to technology. >
Wow. I guess the Blaupunkt/VW approach to product obsolescence started early--filament blows, replace the whole radio. ;) 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
In article <bclckuF4mlnU1@mid.individual.net>,
Joerg  <news@analogconsultants.com> wrote:

>In them days people still knew how it's done. I bet it is possible to >copy a Model 59 using semiconductors, such as dual-gate FETs. But there >is no market. Most kids these days don't have a clue what a dipmeter is. >In fact, whenever I showed up with my Heathkit 1250 the only folks who >knew what that weird thang was were ham radio operators well past the >age of 50.
Agreed... a useful tool, sadly almost forgotten. I've been tempted to (re)build a dipper, using a "lambda diode" arrangement (two JFETs or a JFET and a bipolar) to simulate a classic tunnel-diode oscillator.
>Nowadays you can easily achieve that precision: Use the Model 59 and run >the spectrum analyzer in parallel, using a loop antenna underneath your >work bench. Make it snap to the strongest signal. BTDT. Now, about >changing the display of the spectrum analyzer to megacycles ...
That's one of the more useful applications for a P-Touch labelmaker :-)
On Mon, 21 Oct 2013 15:28:33 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 10/21/2013 02:34 PM, RobertMacy wrote: >> On Mon, 21 Oct 2013 10:55:11 -0700, Joerg <invalid@invalid.invalid> wrote: >> >>>> ...snip... >>> I raise you one: I have a megacycle meter 8-) >>> >>> This one: >>> >>> http://www.ohio.edu/people/postr/bapix/Dip_59.htm >>> >> >> That's too bad you won't be able to use it, since it measures megacycles >> and megacycles no longer exist. Unless you can find some equipment that >> produces megacycles, like...perhaps I can help, I have an original pair >> of WWII walkietalkies! >> >> You have NO idea how long it took me to stop saying >> megacycles/kilocycles and start saying megaHertz/kiloHertz. > >I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is >100 fA FS). Not to be too pico, er, picky. > >Cheers > >Phil Hobbs
I can remember caps (probably out of obsolete equipment at the time) being marked in MMF. I ran across an old design for an optical lever amplifier that used OC71 transistors. Had the misfortune to come into about 1,000 of those things as a wee lad. They almost put me off semiconductors. https://sites.google.com/site/transistorhistory/Home/european-semiconductor-manufacturers/philips 25mW maximum Pd (confused me when I ran into some hydrogen thyratons that were 40MW) -5V maximum Vce (minus plate voltage, what insanity is that? Beta of 50, not great, but not terrible. IIRC, leakage was horrible, uA at room temperature, and rapidly increasing if you approached that 25mW maximum Pd.
Spehro Pefhany wrote:
> On Mon, 21 Oct 2013 15:28:33 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 10/21/2013 02:34 PM, RobertMacy wrote: >>> On Mon, 21 Oct 2013 10:55:11 -0700, Joerg <invalid@invalid.invalid> wrote: >>> >>>>> ...snip... >>>> I raise you one: I have a megacycle meter 8-) >>>> >>>> This one: >>>> >>>> http://www.ohio.edu/people/postr/bapix/Dip_59.htm >>>> >>> That's too bad you won't be able to use it, since it measures megacycles >>> and megacycles no longer exist. Unless you can find some equipment that >>> produces megacycles, like...perhaps I can help, I have an original pair >>> of WWII walkietalkies! >>> >>> You have NO idea how long it took me to stop saying >>> megacycles/kilocycles and start saying megaHertz/kiloHertz. >> I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is >> 100 fA FS). Not to be too pico, er, picky. >> >> Cheers >> >> Phil Hobbs > > I can remember caps (probably out of obsolete equipment at the time) > being marked in MMF. >
Then you aren't old enough. Our forefathers measured capacitance in jars. Later in centimeters.
> I ran across an old design for an optical lever amplifier that used > OC71 transistors. Had the misfortune to come into about 1,000 of those > things as a wee lad. They almost put me off semiconductors. >
They actually brought me to semiconductors. I got a bag of hearing aid size OC transistors of dubious quality, brand name "Fell-of-a-truck". Some leaked terribly, others had other blemishes, but it cost only the equivalent of a couple of Dollars for dozens. Now I could build stuff that ran on a totally exhausted flashlight battery. In Europe they were called "Lady Cells" for some reason, had 3V when fresh, were used to power flashlights. Once under 2V they were discarded, as in "free". I could use them to below 1V with my transistor stuff. Same with depleted D-cells. That would not have worked with Si-transistors (it didn't, I tried later). One of my "innocent" teenage projects was to copy the idea of a bug from some spy movie. I placed it in a flower pot and then could hear my parents talk upstairs in the living room, on longwave (AFAIK only available on radios in Europe). Just for fun, to see if I could pull that off. Later after heading off to university I confessed.
> https://sites.google.com/site/transistorhistory/Home/european-semiconductor-manufacturers/philips > > 25mW maximum Pd (confused me when I ran into some hydrogen thyratons > that were 40MW) > > -5V maximum Vce (minus plate voltage, what insanity is that? >
Didn't the OC71 do 20V Vce?
> Beta of 50, not great, but not terrible. > > IIRC, leakage was horrible, uA at room temperature, and rapidly > increasing if you approached that 25mW maximum Pd. >
Yeah, they all leaked like a sieve. But since one could make circuits that ran at less than a volt one only had to convince family and neighborhood to chuck depleted batteries in this here box instead of the garbage can. Oh, and if you scraped the paint off the glass you could make a nice photo sensor. Try that with contemporary transistors. -- Regards, Joerg http://www.analogconsultants.com/
On Mon, 21 Oct 2013 10:34:38 -0700, RobertMacy
<robert.a.macy@gmail.com> wrote:

>On Mon, 21 Oct 2013 10:20:19 -0700, <krw@attt.bizz> wrote: > >>>> ...snip... >> In my last job I was the only one who wore long pants from April to >> October. Everyone else in Engineering wore T-shirts year 'round. I >> can't do that. I wear long-sleeved shirts (Oxfords, preferred) even >> for mowing the lawn. > >Me too! I paint in a long sleeved Oxford shirt! even in AZ
I have a closet full with paint all over them. ;-)
>My wife is still laughing about the time, on one of our sojourns including >Santa Cruz Boardwalk; I went to get us hotdogs from the boardwalk vendors >in a three piece suit, ...and was carrying my briefcase.
I only wear a suit for funerals, weddings, and the occasional customer trip. In the last 30 years, the first two happened once or so a year and the latter never. Had a couple customer visits (execs, even) last month, though. Seems many more to come.
>In 70's while at Stanford's Chapel for Christmas obaservance, one of my >colleagues wearing a rather worn sweatsuit [it WAS post hippy era] leaned >over and in attempting to ridicule my dress suit asked, "Why do you want >to dress like everyone else?" My reply, "Look around. I'm the ONLY suit >here. Look at you. Why do YOU want to dress like everyone else." And, yes. >EVERYBODY else was in totally casual attire.
;-)