Re: Stopping Lights from Strobing

Bert Haskins
 

On my solder station bench I had a drafting lamp with two 20 w tubes that were a real pita.
I really liked the fixture so I replaced the tubes with dual row led strips powered by a adjustable 12v smps.
Later I added a dimmer.
This ended up being just about all anyone could ask for, just the right amount of light positioned just where you want it.

There is much less glare because the light comes from so many points.

These strips can be very versatile, they can be cut and resoldered for use on 12, 24, 36... volts all the way up to (rectified) 120 AC.

I can furnish pictures upon request.

-- Bert

On 7/14/2018 11:29 PM, Michael A. Terrell wrote:
LEDs don't flicker when fed with clean, filtered DC. The light fixture in my bedroom has three LED bulbs under the ceiling fan and they don't flicker under normal usage. Just before they fail, I have had some start to flash at irregular intervals. All of the LED lamps I've see tell you not to operate them base up, but the only sockets that are base down seem to be table lamps and some outside lamps. I first installed some puny 1.5W LED lamps at the gateposts for my driveway. They were still working when I replaced them with some 7 watt bulbs. In total, there have been LED lamps there for over 15 years without a failure but it is cool when they are on. I've had two failures in two years in my bedroom where they started to flash, then they died.


Michael A. Terrell


-----Original Message-----
From: brians@...
Sent: Jul 14, 2018 10:31 PM
To: TekScopes@groups.io
Subject: [TekScopes] Stopping Lights from Strobing

Many years ago when I was a 'lecky, I worked on a very expensive lathe light fitting that was using fluorescent tubes.

I was amazed that a lathe actually had a fluorescent fitting because of strobe concerns but I found that the manufacturer "cheated" a bit for safety reasons.
Fluorescent light fittings In most commercial use locations have power factor correction capacitors fitted directly across the connection terminals otherwise the power metering will not be correct & there can be circulating current problems.
The manufacturer of the lathe fluorescent light fitting used a dual fluorescent light fitting with two separate ballasts & only had a power factor correction capacitor fitted to the one one fluorescent light.

The power factor correction capacitor caused a phase shift on the one lamp compared to the other.
I actually ran the fitting with no power factor correction capacitors fitted at all & with the one fitted & when the one capacitor was fitted then the strobe effect was not visible.

I suppose that it may be possible to phase shift some LED lamps as well with a capacitor if they use an actual iron transformer for the power supply so you could have dual LED lamps set up in a similar way.

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