LED sensitivity

[ptonsparky]

While on my bucket list tour I noticed that simply turning on the power to our motel room bath fan caused the separate recessed LED can light to flick on just as the the motor started. Two separate toggle switches in a two gang box. Guessing a 3 wire MC cable from the switch box up.

No, I did not put a scope on it and I suspect even adding my T-Plus Pro would have been enough load to stop the blink.

No wonder some of these cause you guys to pull your hair out.

 

[hbiss]

I was just asked about a ceiling paddle fan/light combo. Your usual pull chain switches, one for the lights the other for the fan speeds, nothing special. LED light bulbs were included by the manufacturer.

Put the fan on medium speed and the light bulbs flash. High and low and off, no problem.

Told the guy to change to incandescent bulbs.

-Hal

 

[Flicker Index]

That's due to the poor design of the LED ballast. Inline dimmer (dimmers that wire like traditional dimmers) dimmable LED ballasts are especially prone to glitching due to the ballast that is specifically designed to be as cheap as possible (down to the fraction of cents) becoming confused by line spikes.

 

[gar]

230422-0929 EDT

Most mechanical switches, excluding mercury switches, are noisy ( variation in contact resistance ) when switched. If you switch an inductive load, then you may generate some large transient ( several thousand volt transients during switching, an 8 ft magnetic ballast fluorescent for example ). This can easily cause a momentary flash of an LED bulb.

A shunt load of a series resistor and capacitor may eliminate the LED flash.

.

 

[gadfly56]

I loaned our IT guy my LED flashlight to look at the interior of a computer. He starts cursing a blue streak because the case fan isn't turning. Well, yes it was, it's just the speed happened to match the chopper frequency for the LED bulb and made it look like it wasn't turning. I expect all kinds of artifacts depending on the bulb manufacturer.

 

[ptonsparky]

I loaned our IT guy my LED flashlight to look at the interior of a computer. He starts cursing a blue streak because the case fan isn't turning. Well, yes it was, it's just the speed happened to match the chopper frequency for the LED bulb and made it look like it wasn't turning. I expect all kinds of artifacts depending on the bulb manufacturer.

IIRC that was an issue with early slimline florescents and some rotating equipment. It looked stopped but wasn't.

 

[jim dungar]

IIRC that was an issue with early slimline florescents and some rotating equipment. It looked stopped but wasn't.

Way back when, you could put a 'strobe' disc on your turntable (record player) to check if was really at the proper speed.

 

[ptonsparky]

Way back when, you could put a 'strobe' disc on your turntable (record player) to check if was really at the proper speed.

Seems like some of the turntables had a built in strobe and you adjusted the speed until the dots stood still. Too fancy.

 

[jim dungar]

Seems like some of the turntables had a built in strobe and you adjusted the speed until the dots stood still. Too fancy.

I remember those also.

 

[LarryFine]

I had a Dual 1229 that had a speed strobe.