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OPAMP ASTABLE

Oh! I didn't know such things existed. Hmm for ~$20 I could get a 100V supply. That might be fun... don't think of it as low current, it's a built in current limiter!

George H.

Reply to
George Herold
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We'll never get along. Our definitions of "horrendous spikes" differ by 7 or 8 orders of magnitude.

--

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
Reply to
John Larkin

What sets the frequency?

--

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
Reply to
John Larkin

Depends on your definition of "quiet".

You "design" crap, I design elegance ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Those with half a brain ?>:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Frequency is 1/2 the output slew rate divided by the total output voltage excursion. Output slew rate is just Vin/(Ri x Ci) of the integrator and output voltage excursion is your choice.

Reply to
bloggs.fredbloggs.fred

Makes no sense to me. Got a numerical example? Or Spice model?

--

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
Reply to
John Larkin

Nice device. Could be used for driving isolated FET, with no need for auxiliary supply

Cheers

Klaus

Reply to
Klaus Kragelund

The TLP3902 is a lot cheaper:

formatting link

Cheers

Klaus

Reply to
Klaus Kragelund

Yeah, that looks like the 'intended' application. I'll have to order a handful to play with.

George H.

Reply to
George Herold

I've done that; use my zero-standby-power opto-totem circuit, too.

formatting link

That only makes 5 uA. Probably why it's cheaper... less silicon.

--

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
Reply to
John Larkin

(There's also no stock in the US)

Hey, the TLP590B is a dip! I ordered 10 from mouser. I wonder what the noise is like on the output. With all the junctions in series I bet there's a bit of a temp coef. And then the shot noise will all add. (only in quadrature of course.)

George H.

Reply to
George Herold

I have none on-hand, but I wonder what you get if you take a 4N25, tie output device collector to emitter, call that cathode, and the base as anode... how much current do you get? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

I've got a tube of those... and the answer is,

I LED I sc (mA) (uA) ________________

10 47 20 96 30 143 40 188

Hey if I un-short the collector and emitter I get a the same short circuit current out of one, but much less out of the other only 20uA for 10mA of LED current.

Care to guess, and then tell me why. If I hadn't done the measurement I would have guessed that I'd get less current out of each leg.

George H.

Reply to
George Herold

Not a lot. The efficiency is roughly CTR/beta.

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
Reply to
Phil Hobbs

I'm no expert in photo-induced currents in junctions, but my understanding is that most of it is in the base-emitter path.

(Perhaps because that junction is closest to the surface, but I'm just SWAG-ing :-)

Load it with Larkin's 60K and see what voltage you get. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

A few ma of supply rail spike with a few us risetime is quiet. A few amps in a few ns is noisy.

This is horrible, amps of shoot-through current with sub-ns rise:

formatting link

You called 9 mA of slow spike "horrendous". Why?

I doubt that you could have designed any of my products. Well, maybe one of the trivial accessories.

--

John Larkin         Highland Technology, Inc 

jlarkin at highlandtechnology dot com 
http://www.highlandtechnology.com 

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom laser drivers and controllers 
Photonics and fiberoptic TTL data links 
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply to
John Larkin

There you go with the snot-nosed crap again. Why don't you grow up?

You expressly specified quiet, then posted a distinctly NOT-quiet schematic.

Could you design this...

Not a chance.

I'll be publishing the specifications, some 21 pages, once I cleanse it of any NDA issues.

I doubt you will be able to understand much more of it than the power supply consumption >:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

I tried a Cree T1-3/4 white LED and a Vishay VBPW34S photodiode. With

20 mA / 3 volts on the LED, carefully aligned, I get from the pd 0.52 volts open-circuit, 1.6 mA short-circuit current. That's a CTR of 8% and power transfer of, I'm guessing, around 1%. 
--

John Larkin         Highland Technology, Inc 

jlarkin at highlandtechnology dot com 
http://www.highlandtechnology.com 

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom laser drivers and controllers 
Photonics and fiberoptic TTL data links 
VME thermocouple, LVDT, synchro   acquisition and simulation
Reply to
John Larkin

If you use a longer wavelength LED, you should do better for power transfer, and maybe even CTR.

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
Reply to
Phil Hobbs

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