some prototype coils wound at
cottage coil-winder but it didn't look like a huge place when I dropped in to deliver my formers and winding specifications. Horst is no metropolis.
NRE, or a huge minimum order. I save a bit by putting on the double screening myself - it's a bit fiddly, and doesn't exactly need a coil winding machine.
The SRF0703 can be bought for 20cents. No way you can order custom samples at that price range unless you are asking for +10k lot size.
Regards
Klaus
I found it in Rayner and Kibble's "Coaxial AC Transformers".
William Ayrton died in 1908
so they have been around for a while. Ayrton was a student of Lord Kelvin ( of the Kelvin connection) so his stuff is part of the British electrical in strument tradition, which I got turned on to by reading the Journal of Scie ntific Instruments as a graduate student.
Herman K.P. Neubert's 1963 book "Instrument Transducers" was also influenti al - he introduced me to the Blumlein bridge. Neubert was at the Royal Airc raft Establishment at Farnborough in the UK. My current copy of the book ca me, via Amazon, from the Sandia Corporation Library at Livermore, Californi a - the address was stamped inside the cover and was subsequently over-stam ped "discarded".
-- Bill Sloman, Sydney
that price range unless you are asking for +10k lot size.
Not in Australia
$A 1.19 for 1 to 49. Even for 6,000 it's only down to $A 0.473 And it's only cheap if it does exactly what you want, which doesn't happen often. If you have to add extra components to make it work in your application, it becomes a lot less attractive.
-- Bill Sloman, Sydney
Well, that's not exactly helping here. I do not believe they meant an inductor with that. A part wound Ayrton-Perry style has, in its perfect form, zero inductance.
In those days most people didn't make it to a ripe old age, or rather,
61 was considered old back then.
But even an inductor built by Her Royal Highness the Queen personally will not be an inductor if wound Ayrton-Perry style. The whole purpose of their winding technique is to reduce the inductance to a very small value, ideally to zero.
Sandia is one of the big research labs out here.
-- Regards, Joerg http://www.analogconsultants.com/
Agreed.
-- Mike Perkins Video Solutions Ltd www.videosolutions.ltd.uk
A resistor wound Ayrton-Perry style has close to zero inductance. The think ing that gave them that style of resistor also gave them an astatic inducto r.
Presumably the common perception behind both astatic parts is what is memor ialised in the "Ayrton-Perry" label. They probably published a paper somewh ere ...
His first wife died of TB in 1883. He seems to have died of "arterial disea se"
which would probably have been fixed by Lipitor and a few stents - and mayb e a by-pass operation - today. Coronary heart disease killed a lot of men i n their sixties back then, including the great-grandfather for whom I was n amed.
People did survive into their eighties and nineties, but not as many of the m as do now. The aortic valve I had replaced in 2010 would probably be kill ing me around now if I hadn't had the operation, and my two-years-younger b rother had a quadruple by-pass a few months earlier. My arteries turned out to be a lot cleaner than his when checked out by cine-angiography. The thi rd - even younger - brother, is a medico, and very careful about his his he art.
That's an Ayrton-Perry resistor. The Ayrton-Perry inductor was designed to have a minimum external magnetic field, which is the same idea, but what wo rks for a resistor doesn't work in an inductor.
and the Livermore Labs used to be name to be reckoned with.
-- Bill Sloman, Sydney
US$ 0.33 over yonder in the Wild West:
I am not sure what you are doing but somehow that tends not to happen in my designs :-)
-- Regards, Joerg http://www.analogconsultants.com/
So, where is a live example (meaning at least on the web) of an Ayrton-Perry inductor?
Or as the Romans said, hic Rhodus, hic salta :-)
If it would have been successful that inductor would have shown up on the web, wouldn't it?
[...]-- Regards, Joerg http://www.analogconsultants.com/
For a 6000 unit reel. It's still $0.75 for 1-9, and a lot more than $0.20
I've often found auxiliary windings to be handy.
Sensing the voltage generated across one coil while driving the magnetising current through another is sometimes a useful trick.
-- Bill Sloman, Sydney
On Tue, 04 Jun 2013 21:15:43 +0100, David Jordan wrote:
Here's a little step-up converter that I plan to use in a laser driver, to charge a capacitor bank. It's a tapped-inductor "boostback" circuit. LT Spice claims about 85% efficiency. I included the transformer resistances but no core loss or leakage L. The snubber costs a per cent or so. Needs a little tuning, but looks good. The L and the IC are both tiny.
Version 4 SHEET 1 1840 680 WIRE -320 144 -384 144 WIRE -176 144 -240 144 WIRE -48 144 -176 144 WIRE 112 144 32 144 WIRE 240 144 192 144 WIRE 304 144 240 144 WIRE 432 144 384 144 WIRE 592 144 512 144 WIRE 640 144 592 144 WIRE 752 144 704 144 WIRE 848 144 752 144 WIRE 1008 144 848 144 WIRE 1088 144 1008 144 WIRE 1136 144 1088 144 WIRE 592 176 592 144 WIRE -384 256 -384 144 WIRE 1008 256 1008 144 WIRE 1136 256 1136 144 WIRE -176 272 -176 144 WIRE -80 272 -176 272 WIRE 80 272 -80 272 WIRE 592 288 592 256 WIRE -176 304 -176 272 WIRE 752 304 752 144 WIRE 848 304 848 144 WIRE 80 336 80 272 WIRE 240 336 240 144 WIRE 592 384 592 352 WIRE -384 400 -384 336 WIRE -80 400 -80 272 WIRE 0 400 -80 400 WIRE 1008 400 1008 320 WIRE 1136 400 1136 336 WIRE -176 416 -176 368 WIRE 752 448 752 384 WIRE 752 448 320 448 WIRE 848 448 848 368 WIRE 848 448 752 448 WIRE 1040 464 1008 464 WIRE 1056 464 1040 464 WIRE 0 496 -80 496 WIRE 752 496 752 448 WIRE 1008 496 1008 464 WIRE -80 528 -80 496 WIRE 752 608 752 576 WIRE 1008 608 1008 576 WIRE -80 624 -80 592 WIRE 160 624 160 560 FLAG 1008 608 0 FLAG 1008 400 0 FLAG 1136 400 0 FLAG 1088 144 VP FLAG 160 624 0 FLAG -80 624 0 FLAG 752 608 0 FLAG 592 384 0 FLAG -176 416 0 FLAG -384 400 0 FLAG 1040 464 EFF SYMBOL ind2 96 160 R270 WINDOW 0 -35 52 VTop 2 WINDOW 3 -43 51 VBottom 2 SYMATTR InstName L1 SYMATTR Value 2µ SYMATTR Type ind SYMBOL ind2 288 160 R270 WINDOW 0 -36 59 VTop 2 WINDOW 3 -40 61 VBottom 2 SYMATTR InstName L2 SYMATTR Value 18µ SYMATTR Type ind SYMBOL diode 640 160 R270 WINDOW 0 -40 28 VTop 2 WINDOW 3 -44 29 VBottom 2 SYMATTR InstName D1 SYMATTR Value ES1D SYMBOL cap 992 256 R0 WINDOW 0 -59 -5 Left 2 WINDOW 3 -56 28 Left 2 SYMATTR InstName C1 SYMATTR Value 1µ SYMBOL res 1120 240 R0 WINDOW 0 -51 29 Left 2 WINDOW 3 -53 67 Left 2 SYMATTR InstName R1 SYMATTR Value 1K SYMBOL res -64 160 R270 WINDOW 0 -38 53 VTop 2 WINDOW 3 -44 54 VBottom 2 SYMATTR InstName R3 SYMATTR Value 0.25 SYMBOL PowerProducts\\LT3467 160 448 R0 SYMATTR InstName U1 SYMBOL cap -96 528 R0 WINDOW 0 -55 18 Left 2 WINDOW 3 -60 53 Left 2 SYMATTR InstName C2 SYMATTR Value 20n SYMBOL res 736 288 R0 WINDOW 0 -54 41 Left 2 WINDOW 3 -67 76 Left 2 SYMATTR InstName R2 SYMATTR Value 400K SYMBOL res 736 480 R0 WINDOW 0 61 43 Left 2 WINDOW 3 56 79 Left 2 SYMATTR InstName R4 SYMATTR Value 10K SYMBOL cap 832 304 R0 WINDOW 0 57 22 Left 2 WINDOW 3 49 56 Left 2 SYMATTR InstName C3 SYMATTR Value 3.3p SYMBOL res 576 160 R0 WINDOW 0 -47 53 Left 2 WINDOW 3 -57 89 Left 2 SYMATTR InstName R5 SYMATTR Value 4K SYMBOL cap 576 288 R0 WINDOW 0 -51 25 Left 2 WINDOW 3 -63 60 Left 2 SYMATTR InstName C4 SYMATTR Value 22p SYMBOL cap -192 304 R0 WINDOW 0 -50 18 Left 2 WINDOW 3 -60 50 Left 2 SYMATTR InstName C5 SYMATTR Value 10m SYMBOL res -336 160 R270 WINDOW 0 -38 55 VTop 2 WINDOW 3 -41 53 VBottom 2 SYMATTR InstName R6 SYMATTR Value 10m SYMBOL voltage -384 240 R0 WINDOW 0 48 47 Left 2 WINDOW 3 53 80 Left 2 SYMATTR InstName V2 SYMATTR Value 9 SYMBOL bv 1008 480 R0 WINDOW 0 -88 57 Left 2 WINDOW 3 -229 181 Left 2 SYMATTR InstName B1 SYMATTR Value V = 100 * ( V(VP)**2 / 1000 ) / ( I(R6) * 9 ) SYMBOL res 416 160 R270 WINDOW 0 -36 54 VTop 2 WINDOW 3 -41 54 VBottom 2 SYMATTR InstName R7 SYMATTR Value 1.2 TEXT 192 96 Left 2 !K L1 L2 1 TEXT 456 616 Left 2 !.tran 1m TEXT 80 48 Left 2 ;Coilcraft LPR4012-103DMLB TEXT 376 512 Left 2 ;D140 BOOST CONVERTER TEXT 424 560 Left 2 ;JL June 21 2013
-- 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
And multiply with 60% which is the rule of thumb of the price reduction you get when negotiating price with the distributor instead of the mouser/digikey equivalents
Cheers
Klaus
If I had a toroid, I'd wind you one. Persuading a web-denizen to do somethi ng that useful would take longer. It's actually totally obvious that the ap proach would work - the interesting question is how nearly perfectly astati c the toroidal inductor would be.
There's a well-known - and cute - form of liquid conductivity meter that us es two stacked astatic toroids to measure the conductivity of the fluid in which they are both immersed on the basis that the current induced in the f luid by the first - driven - toroid, which threads the second inductor, ind uces a voltage in the second detecting toroid. Here's an example
They don't say how they make their toroids astatic. They probably hope to h ide it as a trade secret ...
Why? Inductors aren't fashionable, and people go way out of their way to av oid designing transformers.
-- Bill Sloman, Sydney
You can't sketch and scan it?
Not sure what you mean astatic but simply back-threading on a toroid is not an Ayrton-Perry winding.
Sorry, but that's not more than an evasive answer.
-- Regards, Joerg http://www.analogconsultants.com/
[...]
Or use 40% for Asian pricing, and maybe 35% in China :-)
-- Regards, Joerg http://www.analogconsultants.com/
core
Sure? When I ran it R5 showed 140mW, which would come to around 5%. Why not just let the inductor ring out?
What kind of transformer are you using for L1/L2?
-- Regards, Joerg http://www.analogconsultants.com/
core
The ringing might be an EMI issue. I'll probably put the snubber parts on the layout (maybe another one on the fet drain?) in case they are needed.
It's a Coilcraft part. The part number is on the schematic. Tiny little thing.
C1 is 4400 uF in real life. Charging that up will simulate in a bit over 5 hours, 1 second of real time. I could build one and test it a lot faster than that.
I can't trust this sim anyhow.
The LTC data sheet gives the max switch current limit as 2.5 amps, with a typ of
1.8.-- 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
Spice
core
Usually not for radiated, it's typically under 30MHz and has little energy in the radiated field. For conducted you need good line filtering anyhow because of the switch current chop and its harmonics.
Cool, thanks for the hint! Can't get pricing right now. They have this pathetic "system" where if their cookie has been erased you have to enter name, address, shoe size and whatnot to get the price. Over and over again.
That's also what happens if the switcher chip is not a behavioral model like LTC's are. It'll be more accurate but sometimes I had the office temp rise several degrees, just from the PCs. That's ok in January but not so much in August (got to get a 2nd evap cooler here).
I think it's fairly realistic if you correct k and maybe add some parasitics in there. Datasheet says k=0.85.
of
It looks like your design is in the healthy range. Got to correct k to the datasheet value though. Also, you'd probably use a larger soft-start cap in real life.
-- Regards, Joerg http://www.analogconsultants.com/
Spice
core
thing.
of
Minor addition: The winding resistances for the indutor you chose are
0.6ohms and 3.71ohms. Instead of providing extra resistors you can enter them in the inductor itself and click the "make visible" check box.-- Regards, Joerg http://www.analogconsultants.com/
Spice
core
the
thing.
than
typ of
I'm looking into doing a simple single-inductor boost, reasonable at my 5:1 boost ratio. It's much simpler, less junk to snub, no leakage inductance!
-- 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
to
Spice
no core
the
thing.
than
typ of
Simulating switchers isn't as bad as simulating crystal oscillators, but it's close.
-- 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
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