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Phil Hobbs wrote:
> On 2/5/2010 2:13 PM, (E-Mail Removed) wrote: >> On Feb 5, 8:56 am, Phil Hobbs<pcdhSpamMeSensel...@electrooptical.net> >> wrote: >>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback gizmo. >>> I have some Stanley DN310s, but they've been discontinued. Other >>> possibilities are: >>> >>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>> >>> It would be really nice to find something with a flat front facet and >>> (especially) lower capacitance, because it has to work at quite low >>> currents (5-10 uA). >>> >>> Any suggestions? >>> >>> Thanks >>> >>> Phil Hobbs >>> >> >> Isn't low current and high speed mutually exclusive, like intelligence >> and Republicans? >> > Nice try, Soup.  I enjoy talking electronics too much though.> His "email address" always makes me crave miso soup and sushi. So, we just went to the Japanese restaurant in town ... But this time I had pork teriyaki after the miso soup. We usually have sushi in the evenings, I can't really work after that, it's so good that I tend to eat too much of it. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
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(E-Mail Removed) wrote:
> On Feb 5, 2:20 pm, Joerg <inva...@invalid.invalid> wrote: >> Phil Hobbs wrote: >>> On 2/5/2010 2:13 PM, m...@sushi.com wrote: >>>> On Feb 5, 8:56 am, Phil Hobbs<pcdhSpamMeSensel...@electrooptical.net> >>>> wrote: >>>>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback gizmo. >>>>> I have some Stanley DN310s, but they've been discontinued. Other >>>>> possibilities are: >>>>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>>>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>>>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >>>>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>>>> It would be really nice to find something with a flat front facet and >>>>> (especially) lower capacitance, because it has to work at quite low >>>>> currents (5-10 uA). >>>>> Any suggestions? >>>>> Thanks >>>>> Phil Hobbs >>>> Isn't low current and high speed mutually exclusive, like intelligence >>>> and Republicans? >>> Nice try, Soup. I enjoy talking electronics too much though.>> His "email address" always makes me crave miso soup and sushi. So, we >> just went to the Japanese restaurant in town ... >> >> But this time I had pork teriyaki after the miso soup. We usually have >> sushi in the evenings, I can't really work after that, it's so good that >> I tend to eat too much of it. >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ >> >> "gmail" domain blocked because of excessive spam. >> Use another domain or send PM. > > Sushi doesn't make for an evening meal. Just too light, even when > supplemented with miso soup. It's better for lunch. > 4-5 rolls (servings) with 4 people and I am really stuffed afterwards. But it's delicious. > Getting back to electronics., this is really an i=c*dv/dt issue. It > seems to me all you can do is reduce C if current is limited. If Phil has to switch constantly, yes. Otherwise there could be a "spiking circuit" that swings the C with gusto. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
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Phil Hobbs wrote:
> On 2/6/2010 12:41 PM, Joerg wrote: >> (E-Mail Removed) wrote: >>> On Feb 5, 2:20 pm, Joerg <inva...@invalid.invalid> wrote: >>>> Phil Hobbs wrote: >>>>> On 2/5/2010 2:13 PM, m...@sushi.com wrote: >>>>>> On Feb 5, 8:56 am, Phil Hobbs<pcdhSpamMeSensel...@electrooptical.net> >>>>>> wrote: >>>>>>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback >>>>>>> gizmo. >>>>>>> I have some Stanley DN310s, but they've been discontinued. Other >>>>>>> possibilities are: >>>>>>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>>>>>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>>>>>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other specs >>>>>>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>>>>>> It would be really nice to find something with a flat front facet >>>>>>> and >>>>>>> (especially) lower capacitance, because it has to work at quite low >>>>>>> currents (5-10 uA). >>>>>>> Any suggestions? >>>>>>> Thanks >>>>>>> Phil Hobbs >>>>>> Isn't low current and high speed mutually exclusive, like >>>>>> intelligence >>>>>> and Republicans? >>>>> Nice try, Soup. I enjoy talking electronics too much though.>>>> His "email address" always makes me crave miso soup and sushi. So, we >>>> just went to the Japanese restaurant in town ... >>>> >>>> But this time I had pork teriyaki after the miso soup. We usually have >>>> sushi in the evenings, I can't really work after that, it's so good >>>> that >>>> I tend to eat too much of it. >>>> >>>> -- >>>> Regards, Joerg >>>> >>>> http://www.analogconsultants.com/ >>>> >>>> "gmail" domain blocked because of excessive spam. >>>> Use another domain or send PM. >>> >>> Sushi doesn't make for an evening meal. Just too light, even when >>> supplemented with miso soup. It's better for lunch. >>> >> >> 4-5 rolls (servings) with 4 people and I am really stuffed afterwards. >> But it's delicious. >> >> >>> Getting back to electronics., this is really an i=c*dv/dt issue. It >>> seems to me all you can do is reduce C if current is limited. >> >> >> If Phil has to switch constantly, yes. Otherwise there could be a >> "spiking circuit" that swings the C with gusto. >> > > It's inside a feedback loop that needs to have >1 MHz bandwidth, so it's > more a loop stability vs bandwidth issue. There are alternatives, but > they're all more complicated than what we've got. I'd probably prefer > to trade off efficiency rather than speed and capacitance. > Then you'll probably be in the market for the good stuff. This is an example of one I've used in an optical feedback situation. I only needed a little under 100MHz BW but it could have given me a lot more: http://www.excelight.com/pdf/device/...00-x(revC).pdf -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
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On Sat, 06 Feb 2010 15:51:29 -0500, Phil Hobbs <(E-Mail Removed)> wrote:
>On 2/6/2010 3:13 PM, Joerg wrote: >> Phil Hobbs wrote: >>> On 2/6/2010 12:41 PM, Joerg wrote: >>>> (E-Mail Removed) wrote: >>>>> On Feb 5, 2:20 pm, Joerg <inva...@invalid.invalid> wrote: >>>>>> Phil Hobbs wrote: >>>>>>> On 2/5/2010 2:13 PM, m...@sushi.com wrote: >>>>>>>> On Feb 5, 8:56 am, Phil >>>>>>>> Hobbs<pcdhSpamMeSensel...@electrooptical.net> >>>>>>>> wrote: >>>>>>>>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback >>>>>>>>> gizmo. >>>>>>>>> I have some Stanley DN310s, but they've been discontinued. Other >>>>>>>>> possibilities are: >>>>>>>>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>>>>>>>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF typ >>>>>>>>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other >>>>>>>>> specs >>>>>>>>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>>>>>>>> It would be really nice to find something with a flat front >>>>>>>>> facet and >>>>>>>>> (especially) lower capacitance, because it has to work at quitelow >>>>>>>>> currents (5-10 uA). >>>>>>>>> Any suggestions? >>>>>>>>> Thanks >>>>>>>>> Phil Hobbs >>>>>>>> Isn't low current and high speed mutually exclusive, like >>>>>>>> intelligence >>>>>>>> and Republicans? >>>>>>> Nice try, Soup. I enjoy talking electronics too much though.>>>>>> His "email address" always makes me crave miso soup and sushi. So,we >>>>>> just went to the Japanese restaurant in town ... >>>>>> >>>>>> But this time I had pork teriyaki after the miso soup. We usually have >>>>>> sushi in the evenings, I can't really work after that, it's so good >>>>>> that >>>>>> I tend to eat too much of it. >>>>>> >>>>>> -- >>>>>> Regards, Joerg >>>>>> >>>>>> http://www.analogconsultants.com/ >>>>>> >>>>>> "gmail" domain blocked because of excessive spam. >>>>>> Use another domain or send PM. >>>>> >>>>> Sushi doesn't make for an evening meal. Just too light, even when >>>>> supplemented with miso soup. It's better for lunch. >>>>> >>>> >>>> 4-5 rolls (servings) with 4 people and I am really stuffed afterwards. >>>> But it's delicious. >>>> >>>> >>>>> Getting back to electronics., this is really an i=c*dv/dt issue. It >>>>> seems to me all you can do is reduce C if current is limited. >>>> >>>> >>>> If Phil has to switch constantly, yes. Otherwise there could be a >>>> "spiking circuit" that swings the C with gusto. >>>> >>> >>> It's inside a feedback loop that needs to have >1 MHz bandwidth, so >>> it's more a loop stability vs bandwidth issue. There are alternatives, >>> but they're all more complicated than what we've got. I'd probably >>> prefer to trade off efficiency rather than speed and capacitance. >>> >> >> Then you'll probably be in the market for the good stuff. This is an >> example of one I've used in an optical feedback situation. I only needed >> a little under 100MHz BW but it could have given me a lot more: >> >> http://www.excelight.com/pdf/device/...00-x(revC).pdf >> > >Hopefully not--that's megahertz, not gigahertz. But I do want to be >able to work down at 500 nA or 1 uA. > >Cheers > >Phil Hobbs You may wish to consider a laser diode operating below critical current. |
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Phil Hobbs wrote:
> On 2/7/2010 12:29 PM, JosephKK wrote: >> On Sat, 06 Feb 2010 15:51:29 -0500, Phil >> Hobbs<(E-Mail Removed)> wrote: >> >>> On 2/6/2010 3:13 PM, Joerg wrote: >>>> Phil Hobbs wrote: >>>>> On 2/6/2010 12:41 PM, Joerg wrote: >>>>>> (E-Mail Removed) wrote: >>>>>>> On Feb 5, 2:20 pm, Joerg<inva...@invalid.invalid> wrote: >>>>>>>> Phil Hobbs wrote: >>>>>>>>> On 2/5/2010 2:13 PM, m...@sushi.com wrote: >>>>>>>>>> On Feb 5, 8:56 am, Phil >>>>>>>>>> Hobbs<pcdhSpamMeSensel...@electrooptical.net> >>>>>>>>>> wrote: >>>>>>>>>>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical >>>>>>>>>>> feedback >>>>>>>>>>> gizmo. >>>>>>>>>>> I have some Stanley DN310s, but they've been discontinued. Other >>>>>>>>>>> possibilities are: >>>>>>>>>>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 >>>>>>>>>>> pF typ >>>>>>>>>>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pF >>>>>>>>>>> typ >>>>>>>>>>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other >>>>>>>>>>> specs >>>>>>>>>>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>>>>>>>>>> It would be really nice to find something with a flat front >>>>>>>>>>> facet and >>>>>>>>>>> (especially) lower capacitance, because it has to work at >>>>>>>>>>> quite low >>>>>>>>>>> currents (5-10 uA). >>>>>>>>>>> Any suggestions? >>>>>>>>>>> Thanks >>>>>>>>>>> Phil Hobbs >>>>>>>>>> Isn't low current and high speed mutually exclusive, like >>>>>>>>>> intelligence >>>>>>>>>> and Republicans? >>>>>>>>> Nice try, Soup. I enjoy talking electronics too much though.>>>>>>>> His "email address" always makes me crave miso soup and sushi. >>>>>>>> So, we >>>>>>>> just went to the Japanese restaurant in town ... >>>>>>>> >>>>>>>> But this time I had pork teriyaki after the miso soup. We >>>>>>>> usually have >>>>>>>> sushi in the evenings, I can't really work after that, it's so good >>>>>>>> that >>>>>>>> I tend to eat too much of it. >>>>>>>> >>>>>>>> -- >>>>>>>> Regards, Joerg >>>>>>>> >>>>>>>> http://www.analogconsultants.com/ >>>>>>>> >>>>>>>> "gmail" domain blocked because of excessive spam. >>>>>>>> Use another domain or send PM. >>>>>>> >>>>>>> Sushi doesn't make for an evening meal. Just too light, even when >>>>>>> supplemented with miso soup. It's better for lunch. >>>>>>> >>>>>> >>>>>> 4-5 rolls (servings) with 4 people and I am really stuffed >>>>>> afterwards. >>>>>> But it's delicious. >>>>>> >>>>>> >>>>>>> Getting back to electronics., this is really an i=c*dv/dt issue. It >>>>>>> seems to me all you can do is reduce C if current is limited. >>>>>> >>>>>> >>>>>> If Phil has to switch constantly, yes. Otherwise there could be a >>>>>> "spiking circuit" that swings the C with gusto. >>>>>> >>>>> >>>>> It's inside a feedback loop that needs to have>1 MHz bandwidth, so >>>>> it's more a loop stability vs bandwidth issue. There are alternatives, >>>>> but they're all more complicated than what we've got. I'd probably >>>>> prefer to trade off efficiency rather than speed and capacitance. >>>>> >>>> >>>> Then you'll probably be in the market for the good stuff. This is an >>>> example of one I've used in an optical feedback situation. I only >>>> needed >>>> a little under 100MHz BW but it could have given me a lot more: >>>> >>>> http://www.excelight.com/pdf/device/...00-x(revC).pdf >>>> >>> >>> Hopefully not--that's megahertz, not gigahertz. But I do want to be >>> able to work down at 500 nA or 1 uA. >>> >>> Cheers >>> >>> Phil Hobbs >> > >> You may wish to consider a laser diode operating below critical current. > > > Thanks, I know that trick. Thing is, I need a 5000:1 output power > range, or thereabouts--i.e. 3 uW - 15 mW. The bandwidth is going to > be way more than enough at the high end, and the problem is to keep the > feedback poles from crossing at a frequency where there's over-unity gain. > > There are other approaches possible that require different approaches, > but they require more tweaking--e.g. two ranges with two LEDs using > different optical coupling fractions. > Or have an offset in there where the LED (or LD below lasing threshold as Joseph suggested) runs at a regulated base power level. BTDT, but in my case that was in order to remain above lasing threshold. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
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On Sun, 07 Feb 2010 12:56:22 -0500, Phil Hobbs <(E-Mail Removed)> wrote:
>On 2/7/2010 12:29 PM, JosephKK wrote: >> On Sat, 06 Feb 2010 15:51:29 -0500, Phil Hobbs<(E-Mail Removed)> wrote: >> >>> On 2/6/2010 3:13 PM, Joerg wrote: >>>> Phil Hobbs wrote: >>>>> On 2/6/2010 12:41 PM, Joerg wrote: >>>>>> (E-Mail Removed) wrote: >>>>>>> On Feb 5, 2:20 pm, Joerg<inva...@invalid.invalid> wrote: >>>>>>>> Phil Hobbs wrote: >>>>>>>>> On 2/5/2010 2:13 PM, m...@sushi.com wrote: >>>>>>>>>> On Feb 5, 8:56 am, Phil >>>>>>>>>> Hobbs<pcdhSpamMeSensel...@electrooptical.net> >>>>>>>>>> wrote: >>>>>>>>>>> I need a fast IR LED (> 20 MHz,< 50 pF) for an optical feedback >>>>>>>>>>> gizmo. >>>>>>>>>>> I have some Stanley DN310s, but they've been discontinued. Other >>>>>>>>>>> possibilities are: >>>>>>>>>>> Vishay TSFF5410 -- 870 nm, 0.% W/A typ 15 ns rise/fall, 125 pF typ >>>>>>>>>>> Vishay VSLB3940 -- 940 nm, 0.4 W/A typ 15 ns rise/fall, 70 pFtyp >>>>>>>>>>> Panasonic LNA4905L -- 880 nm, 0.3 W/A min 30 MHz typ, no other >>>>>>>>>>> specs >>>>>>>>>>> Osram SFH4550 -- 850 nm, 0.5 W/A typ 12 ns rise/fall, no C spec >>>>>>>>>>> It would be really nice to find something with a flat front >>>>>>>>>>> facet and >>>>>>>>>>> (especially) lower capacitance, because it has to work at quite low >>>>>>>>>>> currents (5-10 uA). >>>>>>>>>>> Any suggestions? >>>>>>>>>>> Thanks >>>>>>>>>>> Phil Hobbs >>>>>>>>>> Isn't low current and high speed mutually exclusive, like >>>>>>>>>> intelligence >>>>>>>>>> and Republicans? >>>>>>>>> Nice try, Soup. I enjoy talking electronics too much though.>>>>>>>> His "email address" always makes me crave miso soup and sushi. So, we >>>>>>>> just went to the Japanese restaurant in town ... >>>>>>>> >>>>>>>> But this time I had pork teriyaki after the miso soup. We usually have >>>>>>>> sushi in the evenings, I can't really work after that, it's so good >>>>>>>> that >>>>>>>> I tend to eat too much of it. >>>>>>>> >>>>>>>> -- >>>>>>>> Regards, Joerg >>>>>>>> >>>>>>>> http://www.analogconsultants.com/ >>>>>>>> >>>>>>>> "gmail" domain blocked because of excessive spam. >>>>>>>> Use another domain or send PM. >>>>>>> >>>>>>> Sushi doesn't make for an evening meal. Just too light, even when >>>>>>> supplemented with miso soup. It's better for lunch. >>>>>>> >>>>>> >>>>>> 4-5 rolls (servings) with 4 people and I am really stuffed afterwards. >>>>>> But it's delicious. >>>>>> >>>>>> >>>>>>> Getting back to electronics., this is really an i=c*dv/dt issue. It >>>>>>> seems to me all you can do is reduce C if current is limited. >>>>>> >>>>>> >>>>>> If Phil has to switch constantly, yes. Otherwise there could be a >>>>>> "spiking circuit" that swings the C with gusto. >>>>>> >>>>> >>>>> It's inside a feedback loop that needs to have>1 MHz bandwidth, so >>>>> it's more a loop stability vs bandwidth issue. There are alternatives, >>>>> but they're all more complicated than what we've got. I'd probably >>>>> prefer to trade off efficiency rather than speed and capacitance. >>>>> >>>> >>>> Then you'll probably be in the market for the good stuff. This is an >>>> example of one I've used in an optical feedback situation. I only needed >>>> a little under 100MHz BW but it could have given me a lot more: >>>> >>>> http://www.excelight.com/pdf/device/...00-x(revC).pdf >>>> >>> >>> Hopefully not--that's megahertz, not gigahertz. But I do want to be >>> able to work down at 500 nA or 1 uA. >>> >>> Cheers >>> >>> Phil Hobbs >> > >> You may wish to consider a laser diode operating below critical current. > > >Thanks, I know that trick. Thing is, I need a 5000:1 output power >range, or thereabouts--i.e. 3 uW - 15 mW. The bandwidth is going to >be way more than enough at the high end, and the problem is to keep the >feedback poles from crossing at a frequency where there's over-unity gain. > >There are other approaches possible that require different approaches, >but they require more tweaking--e.g. two ranges with two LEDs using >different optical coupling fractions. > > >Cheers > >Phil Hobbs Perhaps accurately controllable optical attenuation can be done? Don't know myself but it sounds possible to me. |
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Phil Hobbs wrote:
> On 2/7/2010 5:10 PM, Joerg wrote: >> Phil Hobbs wrote: >>> On 2/7/2010 4:10 PM, Joerg wrote: >>>> Phil Hobbs wrote: >>>>> On 2/7/2010 12:29 PM, JosephKK wrote: >> >> [...] >> >>>>>> You may wish to consider a laser diode operating below critical >>>>>> current. >>>>> >>>>> >>>>> Thanks, I know that trick. Thing is, I need a 5000:1 output power >>>>> range, or thereabouts--i.e. 3 uW - 15 mW. The bandwidth is going to be >>>>> way more than enough at the high end, and the problem is to keep the >>>>> feedback poles from crossing at a frequency where there's over-unity >>>>> gain. >>>>> >>>>> There are other approaches possible that require different approaches, >>>>> but they require more tweaking--e.g. two ranges with two LEDs using >>>>> different optical coupling fractions. >>>>> >>>> >>>> Or have an offset in there where the LED (or LD below lasing threshold >>>> as Joseph suggested) runs at a regulated base power level. BTDT, but in >>>> my case that was in order to remain above lasing threshold. >>>> >>> >>> This gizmo is an advanced photoreceiver that maintains >>> shot-noise-limited performance (2 dB above shot noise) from ~10 nA to >>> 100 uA, with an honest 1 MHz bandwidth over (almost) the whole range. >>> Doing that down near the minimum photocurrent is a real genuine >>> parlour trick. >>> >> >> Luckily I never had to do that. BW was always tens of MHz but they gave >> me plenty of amplitude to work with. However, up there on that pedestal >> it had to be super low noise because we had to extract modulation. >> >> >>> The ones uses two photodiodes wired in series (!) to get a >>> sub-Poissonian photocurrent to null out the primary photocurrent. >>> That's a trick I've never seen before, so I might have invented it. It >>> obviously requires some careful feedback to keep the currents in >>> balance, but the result is a nice linear photoreceiver with almost no >>> additional input capacitance. >>> >> >> Neat! But now you've spilled the beans and can't patent it :-( >> >> Patents aren't worth much anyhow these days. Seems like most of what >> they do is trigger patent trolls who then bog down whole businesses. >> > > I can patent it for the next year, at least in the USA. I might do > that, we'll see. > Just don't wait until T minus 360 days :-) >> >>> Two photodiodes in series have the same photocurrent but *half the >>> shot noise*, so the cancellation current is actually quieter than the >>> photocurrent, without needing resistive degeneration. (I also manage >>> to keep all 300-kelvin resistors out of the signal path, which is key.) >>> >>> The optical feedback is sort of a poor-man's photomultiplier: most of >>> the LED light goes to another photodiode, driving an ordinary TIA >>> which produces the output. It's a really sweet solution overall, with >>> the one disadvantage that it needs two tweaks. >>> >> >> I assume you mean the balancing of the two PDs in series. Is there no >> way to servo that? Maybe by occasionally interrupting the optical path? >> > > There's a bias feedback loop that looks after that. It doesn't have to > be that accurate since the PDs run at 14V of reverse bias--keeping the > junction of the two PDs reasonably still is all that's required. > Good, so it seems automatic. 14V sound like a white-knuckle ride :-) > The tweaks are for making sure that the two photocurrents are reasonably > close to begin with, and to govern the poorly specified efficiency of > the LEDs. (IR LEDs have output power specs that are almost as loose as > the V_T spec of your average JFET.) > > You should be able to buy them in a couple of months, if all goes well. > (No home should be without one, after all.) > Hehe, that's what I used to say as well. No home without a fully certified cardiology ultrasound scanner. And another one for ob/gyn if the freshly married couple is inclined to ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
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