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optical phenom

Started by Anonymous in sci.electronics.design2 years ago 15 replies

I had cataract surgery in one eye and will do the other one soon. I have a pretty high power 400 nm laser. If I shoot it at the wall, the dot...

I had cataract surgery in one eye and will do the other one soon. I have a pretty high power 400 nm laser. If I shoot it at the wall, the dot is bright with the repaired plastic-lens eye and invisible with the one that has the cataract. My doctor explained that a cataract absorbs blue light, and that's why some old ladies color their hair bluish-white, because then it looks right to them. ...


pc motherboard grounds

Started by John Larkin in sci.electronics.design12 years ago 115 replies

The mounting holes on PC motherboards: are they usually connected to the PCB ground plane? -- John Larkin ...

The mounting holes on PC motherboards: are they usually connected to the PCB ground plane? -- 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 d...


coupled resonators

Started by John Larkin in sci.electronics.design9 years ago 17 replies

Cool visual patterns: https://dl.dropboxusercontent.com/u/53724080/Circuits/Oscillators/Coupled_Resonators.jpg The waveforms decay,...

Cool visual patterns: https://dl.dropboxusercontent.com/u/53724080/Circuits/Oscillators/Coupled_Resonators.jpg The waveforms decay, which must be some Spice setting. Ideal resonators wouldn't lose energy. Gear integration is much worse than trap. -- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology...


LED reference current source

Started by John Larkin in sci.electronics.design12 years ago 286 replies

Has anybody done this? https://dl.dropbox.com/u/53724080/Circuits/Isrc_LED.JPG -- John Larkin Highland Technology...

Has anybody done this? https://dl.dropbox.com/u/53724080/Circuits/Isrc_LED.JPG -- 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 V...


really fast buffers

Started by John Larkin in sci.electronics.design5 years ago 95 replies

I'm designing a test board for a laser controller. Incoming signals, fast 5 volt pulses, will need to get routed to scopes, counters, and some...

I'm designing a test board for a laser controller. Incoming signals, fast 5 volt pulses, will need to get routed to scopes, counters, and some other stuff. It will be kind a maze of connectors and traces and probably relays; it's hard to beat a relay as a test path switch. But life would be a lot better if I could fan out some of the signals at their input connector. I want a zero-delay, ze...


Micrel chip test

Started by Anonymous in sci.electronics.design2 years ago 17 replies

Lately we're doing some small 6-layer boards with breakaway tabs for fixturing. So there can be freebie little circuits that snap off. We...

Lately we're doing some small 6-layer boards with breakaway tabs for fixturing. So there can be freebie little circuits that snap off. We use the Micrel SY88022 laser driver in a few off-label applications, and we don't know enough about it, so I hung a test circuit on an upcoming board. https://www.dropbox.com/s/xu559d7y81n4q6g/T502_SY88.jpg?raw=1 This chip is similar to the Maxim...


Improved capacitance multiplier

Started by Phil Hobbs in sci.electronics.design13 years ago 29 replies

So, I had this application requiring really absurd amounts of ripple rejection--it's a piezo driver in a laser wavelength locker that (for...

So, I had this application requiring really absurd amounts of ripple rejection--it's a piezo driver in a laser wavelength locker that (for historical reasons) has to run off a fairly crappy dual isolated 48V DC-DC converter. The 48V has almost a half volt of ripple at 47 kHz, and the output noise needed to be in the nanovolts. As we've discussed here before, ordinary cap multipliers ar...


Cheap, easily milled PCB material

Started by Don Y in sci.electronics.design7 months ago 13 replies

I have to make some dirt cheap boards. I can lay them out single-sided. But, need to be able to mill/route the outlines to relatively...

I have to make some dirt cheap boards. I can lay them out single-sided. But, need to be able to mill/route the outlines to relatively complex shapes (e.g., donuts, concave curves, etc.) One approach is to laser cut the boards -- if the material chosen isn't too "robust" -- instead of having the boardhouse deal with this. The boards don't have to be particularly sturdy as they will be...


See this Fast pulse circuit.

Started by amdx in sci.electronics.design4 years ago 3 replies

I ran across this thread that starts with, "Here is a simple pulse generator I have made for testing medium BW scopes' rise times. It...

I ran across this thread that starts with, "Here is a simple pulse generator I have made for testing medium BW scopes' rise times. It produces flat top signal with clean and fast rise and fall edges." He uses a MAX3949 Laser Driver to generate the signal. He started with 40 to 50 ps and got a little better each iteration. Also, has better connectors if you need them and some ot...


BJT base current 1/f noise

Started by Phil Hobbs in sci.electronics.design6 years ago 87 replies

Is horrible. I'm just debugging a nice diode laser controller for one customer and getting ready to do another one for another (much better)...

Is horrible. I'm just debugging a nice diode laser controller for one customer and getting ready to do another one for another (much better) customer. It uses a ZXTP25020 PNP with a biggish degeneration resistor and two-pole bypassing of the base to get low noise at high frequency. Turns out the 1/f noise is atrocious. The total noise from 2 Hz on up is only a couple of PPM, but it sho...


DDS wisdom

Started by Phil Hobbs in sci.electronics.design9 years ago 152 replies

Hi, all, I have a gig coming in that will have me revisiting my thesis research from nearly 30 years ago, on interferometric laser...

Hi, all, I have a gig coming in that will have me revisiting my thesis research from nearly 30 years ago, on interferometric laser microscopes. (Fun.) Back in the day, I made a nulling-type phase digitizer at 60 MHz by driving a phase shifter with a 12-bit DAC (AD-DAC80), and wrapping a 13-bit successive approximation loop round it (AM2904 with an extra flipflop). With quite a lot ...


the PDP-11 lives!

Started by John Larkin in sci.electronics.design11 years ago 36 replies

http://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep_pdp11_until_2050/ -- John Larkin Highland Technology,...

http://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep_pdp11_until_2050/ -- 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 the...


group photo

Started by Anonymous in sci.electronics.design2 years ago 17 replies

https://www.dropbox.com/s/m8zc7g56jul39d0/NIF_Tour-Highland%20Tech%20group%20photo%20TC.jpg?raw= 1 We got a tour of the NIF laser. That's the...

https://www.dropbox.com/s/m8zc7g56jul39d0/NIF_Tour-Highland%20Tech%20group%20photo%20TC.jpg?raw= 1 We got a tour of the NIF laser. That's the target chamber behind us. On that spot, a Star Trek episode was filmed. https://en.wikipedia.org/wiki/National_Ignition_Facility After 20 years of operation, and roughly 8000 shots, they keep making progress, in the sense of learning stuff and gett


Laser communitions in space

Started by jim whitby in sci.electronics.design8 months ago

Anyone hae any additional info? Excerpt from a Register article ( ) The Deep Space Optical Communications (DSOC) experiment will head off...

Anyone hae any additional info? Excerpt from a Register article ( ) The Deep Space Optical Communications (DSOC) experiment will head off into the void with Psyche, an asteroid-chasing probe that is scheduled to blast off on October 5. While they journey toward 16 Psyche, a metal-rich asteroid


Apex HV opamp issues.

Started by George Herold in sci.electronics.design9 years ago 50 replies

Hi guys (and dolls), So if you read in JL's TI opamp thread, I am having noise issues in our laser diode. I turns out (I think) that the extra...

Hi guys (and dolls), So if you read in JL's TI opamp thread, I am having noise issues in our laser diode. I turns out (I think) that the extra noise is coming from my Piezo drive. The original circuit used a PA141 from Apex. (I can't find a schematic on-line, but I have a hard copy.) Several years ago this HV opamp went away and the recommended replacement from Apex was the PA314 http...


Crystal Controlled Oscillator

Started by Artist in sci.electronics.design2 years ago 53 replies

I have been tasked with designing a piezoelectric actuator driver at its resonant frequency. This is to replace an arrangement where the sine...

I have been tasked with designing a piezoelectric actuator driver at its resonant frequency. This is to replace an arrangement where the sine wave source is a function generator chip (the obsolete XR-2206) that must be individually tweaked on a unit, by unit basis, to match the crystal?s resonant frequency. The crystal is used as an actuator to vibrate a mirror used in a laser syste


Aluminum-core PCB cost?

Started by Phil Hobbs in sci.electronics.design6 years ago 33 replies

I have a customer who wants me to do an extreme shrink of our semi-custom diode laser controller board, which leads to a lot of thermal...

I have a customer who wants me to do an extreme shrink of our semi-custom diode laser controller board, which leads to a lot of thermal issues. The obvious approach is an aluminum-core circuit board, but I've never used one. A few questions for the cognoscenti: 1. Can I get a 6- or 8-layer aluminum-core PCB? 2. How much more do they cost? 3. Any other constraints? Thanks ...


Highly Flexible Cable

Started by Ricketty C in sci.electronics.design4 years ago 23 replies

We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm. The arm swings through up to a 90 degree...

We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm. The arm swings through up to a 90 degree angle with most often a 60 degree angle. I know there are special cords that provide for this sort of flexing. They use cables to connect to printer heads in 3D printers and laser cutting devices. What do they use. -- Rick C. - Get...


picosecond test points

Started by John Larkin in sci.electronics.design12 years ago 70 replies

We're designing some laser driver boards, and I thought it would be cool to add test points to some of the interesting circuit...

We're designing some laser driver boards, and I thought it would be cool to add test points to some of the interesting circuit nodes. Regular scope probes don't work at ps speeds, and probe grounding is difficult. There are multi-GHz active probes, at roughly $1 per Hz. So I was thinking that I could add a small, 0603 maybe, resistor to a signal to be snooped, run a 50 ohm trace some sm...


cotton-pickin Pulse Picker

Started by Winfield Hill in sci.electronics.design8 years ago 23 replies

Some reading for a lazy Sunday afternoon. A typical femto-second laser might give 65kW 0.1ps light pulses at a rate of 80MHz. But some...

Some reading for a lazy Sunday afternoon. A typical femto-second laser might give 65kW 0.1ps light pulses at a rate of 80MHz. But some applications can't handle a powerful light pulse every 12.5ns, for example fluorescence-lifetime measurements (we don't want to re-excite any molecules before achieving 100% decay). The solution is to add a light modulator, and run it from a pulse-picker. ...