[time-nuts] Reducing lab noise with LED lighting
You have apparently not tried any modern/quality LED bulbs. The Sylvania Ultra series have a 95 CRI (color rendering index). Bridgelux makes some arrays with a CRI over 98. I defy you to tell the difference between the output of those bulbs (or any LED with a CRI over 85) and halogens. My house has a lot of artwork that is now lit by LEDs. I've has a couple of museum directors by and they couldn't. As far as LED flicker is concerned, lots of LED flashlights dim via a PWM signal. Lots of people can see PWM effects up to over 400 Hz! It shows up like a strobe light effect when the beam is moved around. Also, white LEDs are NOT pumped by UV. The LED underneath the phosphor is a royal blue color. Lighting LEDs produce no spectrum in the UV or IR bands... that is one reason museums and art galleries use them. -- Personally I find the light spectrum from the CFL's and LED's to be very unpleasant. I have had to add an incandescent to the lighting in my office to keep my eyes from straining. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
Has anyone tried the fluorescent replacement LED tubes? Apparently you remove the ballast from the fixture and power the tube from the 120V AC line. Any chance these would reduce the noise in a lab from conventional fluorescent tubes? Thanks. attachment: smither.vcf___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
I've tried that with a replacement tube that worked with the original ballast, all you had to do was remove the starter. The results were horrible. The tube was about a metre above my scope and waving the probe about showed horrible spikes and damped oscillatory waveforms up to several volts in amplitude. Needless to say I'm back to a conventional fluoro. The discussion about LED flicker was interesting. As I understand it the human eye can act as a peak detector so it responds quite well to pulsed lights at a high enough frequency. I'm currently (boom boom) illuminating an ornamental vacuum tube display with a strip of white LEDs powered by full wave rectified but unfiltered DC at 100 Hz (in a 50 Hz country). It's in an otherwise dim corner and there's never been any hint of visible flicker to me or anyone else. Morris Date: Tue, 18 Sep 2012 17:22:44 -0500 From: Bob Smither smit...@c-c-i.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Reducing lab noise with LED lighting. Has anyone tried the fluorescent replacement LED tubes? Apparently you remove the ballast from the fixture and power the tube from the 120V AC line. Any chance these would reduce the noise in a lab from conventional fluorescent tubes? Thanks. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
On Tue, Sep 18, 2012 at 7:49 PM, Morris Odell vilgo...@bigpond.net.au wrote: The discussion about LED flicker was interesting. As I understand it the human eye can act as a peak detector Actually the rods and cones in the retina only respond the changes in brightness. the eye constantly moves so that the image always changes. It works this way because we needed to see only edges. We don't see 120Hz as flicker but still it stresses the eyes and visual system. If you think of the eye as being AC coupled to the brain it is easy to understand why to fast to see fast flicker is fatiguing. Back to noise in the lab: As I wrote a while back if you want efficient lighting that is radio quiet all you have to do is shop in the right store. Much of the lighting used in ocean going sail boats is quiet because these boats will cary HF and VHF radio, GPS and radar and run off battery power. But don't expect radio-quiet cold cathode fluorescent lamps made from power coated stainless steel to be cheap, you pay for the quality. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
Some of the LED assemblies are stacks of diodes and the Vf is 2.5 to 3.5 volts. How about powering them from a 3.3 volt PC supply? Plenty of amps available and those switchers have typically had to have their EMI emissions cleaned up. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Sunday, September 16, 2012 8:09 PM To: Time-Nuts Subject: [time-nuts] Reducing lab noise with LED lighting. In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
I think I poorly explained my thoughts. I noticed on eBay that high powered raw LED arrays like this one 20W Warm White LED Lamp Chip 2800-3500K Bright Light Bulb... (170902780218) are now for sale at reasonable prices. Do not let the wattage's fool you, If you have not seen one of these arrays you will be shocked. the 10 watt version usally use 12 volts, Most of these 20-100 watts run on 36vdc, I do not think driving these with a clean switcher will add to lab noise VS CFL. One of my benches has standard 2 x 48 inch florescent tubes. I was going to mount 5 of these on a 48 inch aluminum extrusion with the supply inside the old fixture. This would be very very bright (Perhaps to bright) with just over 100 watts draw. The conversion will cost about $100 on the surplus market if you had none of the needed items and should pay for it self over the next few years in energy costs. Thomas Knox From: thol...@woh.rr.com To: time-nuts@febo.com Date: Mon, 17 Sep 2012 10:21:07 -0400 Subject: Re: [time-nuts] Reducing lab noise with LED lighting. Some of the LED assemblies are stacks of diodes and the Vf is 2.5 to 3.5 volts. How about powering them from a 3.3 volt PC supply? Plenty of amps available and those switchers have typically had to have their EMI emissions cleaned up. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Sunday, September 16, 2012 8:09 PM To: Time-Nuts Subject: [time-nuts] Reducing lab noise with LED lighting. In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
As even LED have switchers in them, look for 12V LED spot lamps which run on AC/DC and give them a try. They have 3 LEDs and I don't think they have a switcher PS. A 12V transformer PS will work without filter cap IMHO. Low noise ! At 17-09-2012, you wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
AllElectronics has has some ~24, 24 white LED white strips available for about $7 of late. I purchased a bunch and stick them under the lips of the shelves in my office/lab and powered them with an old laptop brick I had sitting about. Look great, wickedly cheap, and very effective, especially at night. On Mon, Sep 17, 2012 at 11:10 AM, Raj vu2...@gmail.com wrote: As even LED have switchers in them, look for 12V LED spot lamps which run on AC/DC and give them a try. They have 3 LEDs and I don't think they have a switcher PS. A 12V transformer PS will work without filter cap IMHO. Low noise ! At 17-09-2012, you wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
Hi I think you will find that a constant current source is what you are after as a driver. That's not a hard thing to do, if you plan for it from the start. I'd be careful about just which switcher you decide to use. A switcher that's plenty quiet inside a PC case can be a bit noisy when attached to 50' of wire. I've spent a lot of time swapping out conventional light ballasts to get a lab that's quiet enough for phase noise work... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Monday, September 17, 2012 11:09 AM To: Time-Nuts Subject: Re: [time-nuts] Reducing lab noise with LED lighting. I think I poorly explained my thoughts. I noticed on eBay that high powered raw LED arrays like this one 20W Warm White LED Lamp Chip 2800-3500K Bright Light Bulb... (170902780218) are now for sale at reasonable prices. Do not let the wattage's fool you, If you have not seen one of these arrays you will be shocked. the 10 watt version usally use 12 volts, Most of these 20-100 watts run on 36vdc, I do not think driving these with a clean switcher will add to lab noise VS CFL. One of my benches has standard 2 x 48 inch florescent tubes. I was going to mount 5 of these on a 48 inch aluminum extrusion with the supply inside the old fixture. This would be very very bright (Perhaps to bright) with just over 100 watts draw. The conversion will cost about $100 on the surplus market if you had none of the needed items and should pay for it self over the next few years in energy costs. Thomas Knox From: thol...@woh.rr.com To: time-nuts@febo.com Date: Mon, 17 Sep 2012 10:21:07 -0400 Subject: Re: [time-nuts] Reducing lab noise with LED lighting. Some of the LED assemblies are stacks of diodes and the Vf is 2.5 to 3.5 volts. How about powering them from a 3.3 volt PC supply? Plenty of amps available and those switchers have typically had to have their EMI emissions cleaned up. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Sunday, September 16, 2012 8:09 PM To: Time-Nuts Subject: [time-nuts] Reducing lab noise with LED lighting. In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Reducing lab noise with LED lighting.
I have considerable experience with LED lighting. My house has over 300 light bulbs in it! They are now all LED bulbs. You can read about some of it here: http://budgetlightforum.com/node/9179 A few observations and recommendations: Avoid all Chinese led bulbs. They spew more hash than a cheap diner. Also I have never seen one that meets it's output specs. Only use bulbs from well known, name brand makers. I like Sylvania/Osram, Philips, and Lighting Science Group bulbs. Avoid those Chinese LED array chips. Their light quality tends to the bad side of awful and again I've never seen one meet their advertised specs. Look into arrays made by Bridgelux. They have proper datasheets and specs. Do not drive an led with rectified AC... 120 Hz flicker can be quite noticeable with an LED. You CAN direct drive an LED with a regulated voltage. You have to match the voltage to the LED and be aware of the Vf shift as the LED heats up. A ballast resistor helps even things out. An LED driven through a ballast resistor can be more efficient than a switching regulator/current source if you choose your voltage source to be close to the LED Vf. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Reducing lab noise with LED lighting
Personally I find the light spectrum from the CFL's and LED's to be very unpleasant. I have had to add an incandescent to the lighting in my office to keep my eyes from straining. -- Joe Leikhim President Leikhim and Associates Oviedo Florida 407-982-0446 jleik...@leikhim.com www.leikhim.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting
My point with halogens. I have LEDs for space lighting in my house but for anything involving reading or close-up work, it is halogen. I am also a photographer so color balance matters to me. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim Sent: Monday, September 17, 2012 21:31 To: time-nuts@febo.com Subject: [time-nuts] Reducing lab noise with LED lighting Personally I find the light spectrum from the CFL's and LED's to be very unpleasant. I have had to add an incandescent to the lighting in my office to keep my eyes from straining. -- Joe Leikhim President Leikhim and Associates Oviedo Florida 407-982-0446 jleik...@leikhim.com www.leikhim.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Reducing lab noise with LED lighting.
In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
Hi The thing that makes the CFL's nasty for lab use are the cheap little switchers built into them. Conventional LED lights also have cheap little switchers in them. Doing them with a 30% efficient linear regulator gets you back to halogen type lumens per watt... Bob On Sep 16, 2012, at 8:09 PM, Tom Knox act...@hotmail.com wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
Another good source of low-noise lighting is marine hardware stores. I owned a sailboat for a while. Sailboats are floating radio stations. I had Marine HF and VHF and Radar all running off banks of lead acid batteries. You have the same noise issues on the water as in ham radio stations.So many of the lighting products are designed to be radio-quiet and will say they are quiet on the box. The LEDs are good, if the power supply is clean but like all power supplies you have to check. Actually the CFLs are radio quiet too it is the little power supply built into the base that makes the noise. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
I've seen lots of halogen power supplies which use cheap switchers too! On 9/16/2012 8:55 PM, Bob Camp wrote: Hi The thing that makes the CFL's nasty for lab use are the cheap little switchers built into them. Conventional LED lights also have cheap little switchers in them. Doing them with a 30% efficient linear regulator gets you back to halogen type lumens per watt... Bob On Sep 16, 2012, at 8:09 PM, Tom Knox act...@hotmail.com wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5271 - Release Date: 09/16/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
HI Most of my little desktop cheap halogens got turned into LED's a while back. Forgot about them…. Bob On Sep 16, 2012, at 9:06 PM, Peter Gottlieb n...@verizon.net wrote: I've seen lots of halogen power supplies which use cheap switchers too! On 9/16/2012 8:55 PM, Bob Camp wrote: Hi The thing that makes the CFL's nasty for lab use are the cheap little switchers built into them. Conventional LED lights also have cheap little switchers in them. Doing them with a 30% efficient linear regulator gets you back to halogen type lumens per watt... Bob On Sep 16, 2012, at 8:09 PM, Tom Knox act...@hotmail.com wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy so I have started researching cost effective LED lighting and was amazed at what is available. On eBay there are 10 to 100 watt raw chips for $2-25.00 but that is equal to about 5 times the lumen of incandescent lighting. I was going to try building the heat sinks and supply into my existing bench fixtures. I will post more info soon. Thomas Knox ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5271 - Release Date: 09/16/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
On 9/16/2012 8:09 PM, Tom Knox wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy Run 12 VDC lighting, or hydrocarbon (NG/propane/naptha, which is noisy in a different way. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
12 volt Halogen from a big transformer run from a Variac if you want dimming. As long as the Variac brushes aren't arcing that setup will create zero noise. On 9/16/2012 9:55 PM, Mike S wrote: On 9/16/2012 8:09 PM, Tom Knox wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy Run 12 VDC lighting, or hydrocarbon (NG/propane/naptha, which is noisy in a different way. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5271 - Release Date: 09/16/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
If you dim the halogens, you will be operating them outside of the temperature required for the Halogen Cycle to operate. http://en.wikipedia.org/wiki/Halogen_lamp Shorter filament life and bulb darkening. That being said, I have a couple of halogen lights on dimmers and love them -- I like the quality of the light. DaveH -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: Sunday, September 16, 2012 19:26 To: time-nuts@febo.com Subject: Re: [time-nuts] Reducing lab noise with LED lighting. 12 volt Halogen from a big transformer run from a Variac if you want dimming. As long as the Variac brushes aren't arcing that setup will create zero noise. On 9/16/2012 9:55 PM, Mike S wrote: On 9/16/2012 8:09 PM, Tom Knox wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy Run 12 VDC lighting, or hydrocarbon (NG/propane/naptha, which is noisy in a different way. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5271 - Release Date: 09/16/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reducing lab noise with LED lighting.
In message 9ae0e07a-568c-43d1-8cb6-0d0e21ee6...@rtty.us, Bob Camp writes: The thing that makes the CFL's nasty for lab use are the cheap little switchers built into them. Conventional LED lights also have cheap little switchers in them. Doing them with a 30% efficient linear regulator gets you back to halogen type lumens per watt... I run my led-lights directly off my 12V battery backed supply without any regulation, just find the right number of LEDS to connect in series for the maximum charge voltage, and live with a little less light in hold-over mode... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
