Congrats, Q.E.D.!

This was your first one, verdad?

No, this was my first one. :smiley:

But, thanks anyway.

Congrats! Here’s to many more :slight_smile:


Must have been the month I was skipping the front page.

fake sig

Ha! Well forgive me if a don’t do a cartwheel of joy; your family’s history in the department of cunning planning is about as impressive as Stumpy O’Leg McNolegs’ personal best in the Market Harborough marathon.

Hey Q.E.D., I was going to post this in GQ, but I’ll just ask you, since it’s related to your column. (Mods, forgive me if I’m asking in the wrong place.)

After reading your excellent report, I was left wondering what is used now to replace the ballast? Also, why don’t modern lamps flicker? I have many of the compact fluorescent lamps in my office, and they appear to be self-contained. Any thoughts? Thanks

There is a ballast, lightingtool, however these days, it’s an electronic one, operating in the neighborhood of 20 kHz, so there’s no flicker.

Love the fake sig, NCB. :wink:

My own follow-up question is how to reduce the buzzing, if possib le.

My second follow-up question is how do I get a chance to write for the Dope?

Bryan, drop a line to C K Dexter Haven and tell him what sorts of things you feel knowledgeable enough about to answer questions concerning.

As for stopping the buzzing, the only practical thing to do is to replace the ballast.

This set me to thinking … what could I contribute to the fund of knowledge on the Straight Dope?

And I realised I know nothing about anything at all! :frowning:

Oh well … on with the daily grind …


Well, we need someone to read 'em Staff Reports as well, no ? :stuck_out_tongue:

QED, perhaps you should have noted that the core of inductors or transformers (that are iron core and sufficiently big like those found in ballasts) are made up laminations. Once stacked they are stuck into a frame, get bolted, rivited, etc. and sometimes get “varnished” as well. Most of the “lovely” buzzin’ is due to the individual pieces of the laminated core rattling against the layer(s) next to it. But, perhaps that is taking it too far, eh? I personally like the electronic versions better since they don’t make noise, don’t ooz goo out when they go really bad, tend to last much longer and will start tubes under colder conditions (the tubes used play a role in that too).

One of previous jobs was working in a plant which built transformers and inductors, primarily for milspec and aerospace applications, but we also had a commercial division that made gas-discharge lamp ballasts. Occassionally we would have to design a new transformer for a customer, or rework an existing design. Since many of our transformers were being used in commercial jetliners, whose power systems operate at 400 Hz, noise was often a critical factor (listen to an 800 Hz whine and you’ll understand why). Often a new design would be noisy, and we’d have to figure out why. The noisiest ones we ever made were three-phase units for the 737 and 747, and went under the cockpit someplace, I believe. Boeing was a bit upset when a redesign of this unit began irritating pilots, who could hear the whine of these things above all the other sounds in the cockpit. This particular transformer was cored with a tape-wound cut C-core, which is essentially a length of silicon-steel tape wound on a former, then cut in half. The two halves are assembled into the windings and banded with a stainless steel strap at 150 pounds of pressure. There was no looseness and no way for lams to vibrate together. We eventually determined it was strictly a magnetostrictive effect and solved the problem by damping the sound by encapsulating the core in RTV silicone. And that’s my fun noisy core story for the day.

**QED[;/b]. In case I forgot, you do some good work. Not to mention you’re fast. And now that I read your last post, my mind boggles.

Good to have you doing this stuff.

So … I take it that this means DC fluorescent lights (e.g. battery-powered lanterns) do not and cannot buzz at all, then?

Those battery or DC-powered fluorescent lamps use an inverter–a circuit that converts the DC to a higher-voltage AC. They usually operate at 15-20 kHz, which is beyond the normal range of hearing for most people. Some people might hear a high-pitched whine, just like some people can hear the 15.75 kHz whine of NTSC TVs.

Then what, pray tell, does one do when the NEW one buzzes just about as the old one? I can tell you what I did. Removed the blasted fixture and replaced it with incandescent.

Nice job, Q.E.D. You are one smart cookie! Thanks for…er…illuminating us. :slight_smile:

I’ll second that! Huzzah!!!

One real cool thing Q.E.D. has is a great way with search engines.

If’n him don’t be know’n its right off, him can be find’n its real quick like.

This is so the voltage’ll be high enough to vaporize the mercury and exceed the breakdown voltage of the gas mixture, right?

I mean, if I were to apply a super-high-voltage DC battery to a fluorescent lamp, I wouldn’t need to convert the current to AC, would I?


I have always wondered about that… No one ever believes me when I talk about that sound.