Optical Attenuator/switches... any one ever even seen these. Opto isolated FETs - diyAudio
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Old 22nd May 2010, 07:32 AM   #1
Mooly is offline Mooly  United Kingdom
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Default Optical Attenuator/switches... any one ever even seen these. Opto isolated FETs

With all the recent threads on attenuators and the "lightspeed" etc, wondered if anyone had ever come across this type of device.

First saw these in Elektor around 25 years ago (in an AGC circuit) and never seen the devices since.
http://www.nteinc.com/specs/3000to3099/pdf/nte3085.pdf

Wonder how they could be made to perform... noise/tracking etc. 100ohm to 300meg ohms is the quoted range of "resistance"
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Old 22nd May 2010, 09:08 AM   #2
Nrik is offline Nrik  Denmark
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That surely looks nice :-)
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Old 22nd May 2010, 09:31 AM   #3
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hei mooly ...ever had in your life an nte thing that works properly ??? ...
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Old 22nd May 2010, 09:44 AM   #4
gfle is offline gfle  Greece
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IS610 is the original part.
http://pdfdata.datasheetsite.com/web/59082/IS610.pdf
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Old 22nd May 2010, 11:44 AM   #5
Mooly is offline Mooly  United Kingdom
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Quote:
Originally Posted by sakis View Post
hei mooly ...ever had in your life an nte thing that works properly ??? ...
can't recall having come across the NTE brand before for DIY parts... might have some old germaniums marked NTE, not sure.

You had bad experience ?
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Old 22nd May 2010, 11:45 AM   #6
Mooly is offline Mooly  United Kingdom
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Quote:
Originally Posted by gfle View Post
Thanks for the link... keep thinking back to the old Elektor mag (summer circuits ?). Was it a dual or quad device even. Wish I had kept a lot of the old mags now.
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Old 22nd May 2010, 12:54 PM   #7
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I'm not sure if I fully understand your question.
Do you mean, specifically come accros this NTE thing? No.
But I've used the panasonic photomos switches, which are optically isolated FETs.
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Old 22nd May 2010, 03:29 PM   #8
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I like the IL300 from Vishay. It has two matched photodiodes so that one of them can be used to servo the LED in order to linearize its characteristics. Great BW too. I have played with it in both photoconductive and photovoltaic mode. I use a couple of them in my latest amp circuit in photoconductive but only for DC bias control, not for signal coupling. I wonder if it would be possible to use one in place of the input cap? I am seriously considering giving it a try. One thing I hate in SS amps is coupling capacitors of any kind. The input cap is a requirement but if I can replace it with one of these linearized opto-couplers it would be cool. Hmm, maybe I should test it as an input coupler and see how it sounds first.
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Old 22nd May 2010, 04:37 PM   #9
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nielsen media research used to use those for metering video game switches and other devices...
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Old 22nd May 2010, 05:05 PM   #10
Mooly is offline Mooly  United Kingdom
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Some interesting devices out there for sure. The IL300 is another new one to me... thanks CBS240

krashkiste... The photomos relays are interesting... I remembered this thread a while back, have a look at post #6

http://www.diyaudio.com/forums/solid...et-relais.html

Any photomos ones high enough rated for this application i wonder.

It's good to see what's "out there"... you never know when you have an idea that can use it.
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