Semi OT, new overhead LED lights in T-8 size tube

[George Herold]

So a week or two ago they put new LED T-8 (4') bulbs overhead in my lab.
Today I was doing some noise testing and I wondered how 'bad' the new bulbs were.
They are great, a quick survey and I could see no peaks in my noise spectrum.
So I grabbed a photodiode to look at them... The light is a beautiful 120 Hz
signal.
https://www.dropbox.com/s/rwl7kkfrtc0yyep/LED_lamp1.bmp?dl=0

When I looked close in (AC coupling, same gain for photodiode) there are
'steps' at ~50 kHz... but dang small.
https://www.dropbox.com/s/yimhhxhbxa8soh2/Led_lamp2.bmp?dl=0

Sweet!

George H.

 

[Jon Elson]

On Thu, 15 Aug 2019 13:09:04 -0700, George Herold wrote:

So a week or two ago they put new LED T-8 (4') bulbs overhead in my lab.
Today I was doing some noise testing and I wondered how 'bad' the new
bulbs were.
They are great, a quick survey and I could see no peaks in my noise
spectrum.
So I grabbed a photodiode to look at them... The light is a beautiful
120 Hz signal.
https://www.dropbox.com/s/rwl7kkfrtc0yyep/LED_lamp1.bmp?dl=0

When I looked close in (AC coupling, same gain for photodiode) there are
'steps' at ~50 kHz... but dang small.
https://www.dropbox.com/s/yimhhxhbxa8soh2/Led_lamp2.bmp?dl=0

Wow, that's amazingly good! I know the old-style T12 fluorescents in our
lab are fairly noisy. Horrible noise when the rapid-start circuit is
lighting the lamps, and then some noise when they are running. But, in a
crazy way, that is good, as we do a lot of noise-susceptible gear, so if
it runs well in the lab, we know we are in fairly good shape for EMI
susceptibility.

Jon

 

[John Larkin]

On Thu, 15 Aug 2019 13:09:04 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

So a week or two ago they put new LED T-8 (4') bulbs overhead in my lab.
Today I was doing some noise testing and I wondered how 'bad' the new bulbs were.
They are great, a quick survey and I could see no peaks in my noise spectrum.
So I grabbed a photodiode to look at them... The light is a beautiful 120 Hz
signal.
https://www.dropbox.com/s/rwl7kkfrtc0yyep/LED_lamp1.bmp?dl=0

When I looked close in (AC coupling, same gain for photodiode) there are
'steps' at ~50 kHz... but dang small.
https://www.dropbox.com/s/yimhhxhbxa8soh2/Led_lamp2.bmp?dl=0

Sweet!

George H.

We have fancy new LED lights in our office. I threw a wire on top of
one, to a scope, and found essentially no EMI. Fluorescents with
electronic ballasts are terrible.

They also have annoying smart motion sensors, required by law here. I
disabled the one in my office, because I don't much like overhead
lighting and they were always turning on and off when they felt like
it.

https://www.dropbox.com/s/mc2odpc0h4nx8oe/JL_Office.JPG?raw=1

They are 10 volt dimmable, which I might get into with a pot some day.
Meanwhile, they are just off.

The whiteboard light kept falling off the cabinet, so I added LED
spots.

https://www.dropbox.com/s/wnyn4nxw41apf22/WB_Lights.JPG?raw=1

and a dedicated camera.

https://www.dropbox.com/s/0c40wrvt6t89shj/WB_Cam.JPG?raw=1

 

[George Herold]

On Thursday, August 15, 2019 at 7:03:31 PM UTC-4, John Larkin wrote:

On Thu, 15 Aug 2019 13:09:04 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:

So a week or two ago they put new LED T-8 (4') bulbs overhead in my lab.
Today I was doing some noise testing and I wondered how 'bad' the new bulbs were.
They are great, a quick survey and I could see no peaks in my noise spectrum.
So I grabbed a photodiode to look at them... The light is a beautiful 120 Hz
signal.
https://www.dropbox.com/s/rwl7kkfrtc0yyep/LED_lamp1.bmp?dl=0

When I looked close in (AC coupling, same gain for photodiode) there are
'steps' at ~50 kHz... but dang small.
https://www.dropbox.com/s/yimhhxhbxa8soh2/Led_lamp2.bmp?dl=0

Sweet!

George H.

We have fancy new LED lights in our office. I threw a wire on top of
one, to a scope, and found essentially no EMI. Fluorescents with
electronic ballasts are terrible.

I test the electrostatic leakage on this noise box with the
overhead lights... or use to... I'll have to ask them to save me a
ballast and tubes for testing. I think they are throwing them out.

I could build my own electrostatic noise source.. but it might be
illegal.

George H.

They also have annoying smart motion sensors, required by law here. I
disabled the one in my office, because I don't much like overhead
lighting and they were always turning on and off when they felt like
it.

https://www.dropbox.com/s/mc2odpc0h4nx8oe/JL_Office.JPG?raw=1

They are 10 volt dimmable, which I might get into with a pot some day.
Meanwhile, they are just off.

The whiteboard light kept falling off the cabinet, so I added LED
spots.

https://www.dropbox.com/s/wnyn4nxw41apf22/WB_Lights.JPG?raw=1

and a dedicated camera.

https://www.dropbox.com/s/0c40wrvt6t89shj/WB_Cam.JPG?raw=1

 

[mpm]

On Thursday, August 15, 2019 at 4:09:08 PM UTC-4, George Herold wrote:

So a week or two ago they put new LED T-8 (4') bulbs overhead in my lab.
Today I was doing some noise testing and I wondered how 'bad' the new bulbs were.
They are great, a quick survey and I could see no peaks in my noise spectrum. ....

The boss just replaced all the lights with LED tubes he got on eBay (or, really, who cares where). They flicker all day. Especially when the fuser element on a printer warms up to print.

He now wants to spend money on line conditioning equipment (which I suspect may not help). Oh, and the dimmable LED's he bought from Alibaba (or again, who gives a shit?)... they don't DIM.

Perfect.

This is the same guy who manages the SIP phones in our office, and most of the network (except for Engineering). On most days, ours is the only network running. It's too bad he's the boss or all these problems could be fixed.
But I've given up. The office lights flicker so much now that you hardly even notice. But at least they're at full brightness.

 

[George Herold]

On Thursday, August 15, 2019 at 9:06:59 PM UTC-4, mpm wrote:

On Thursday, August 15, 2019 at 4:09:08 PM UTC-4, George Herold wrote:
So a week or two ago they put new LED T-8 (4') bulbs overhead in my lab.
Today I was doing some noise testing and I wondered how 'bad' the new bulbs were.
They are great, a quick survey and I could see no peaks in my noise spectrum. ....

The boss just replaced all the lights with LED tubes he got on eBay (or, really, who cares where). They flicker all day. Especially when the fuser element on a printer warms up to print.

He now wants to spend money on line conditioning equipment (which I suspect may not help). Oh, and the dimmable LED's he bought from Alibaba (or again, who gives a shit?)... they don't DIM.

Perfect.

This is the same guy who manages the SIP phones in our office, and most of the network (except for Engineering). On most days, ours is the only network running. It's too bad he's the boss or all these problems could be fixed.
But I've given up. The office lights flicker so much now that you hardly even notice. But at least they're at full brightness.

The name on the bulbs is Starco lighting... huh they seemed to be based out of the
same building I work in... that explains a lot.

https://starcous.com/

George H.