Incandescent bulbs in teaching

[Drakkith]

Well, I just bought a lamp that lights up without any lightbulb. And the surface that lights up stays at room temperature

LED?

 

[WWGD]

LED?

Yes. It had me at $2.50. Though I have no idea where the heat sink is.

 

[Swamp Thing]

I started my career at a company that made electronic test instruments. One of those was an audio signal generator. It used a Wien bridge oscillator as the basic source.

Of course, these circuits would produce unacceptable harmonic output if the oscillator was allowed to build up to a level limited only by supply voltage and other nonlinearities. So it contained a deceptively simple but highly effective level control. The oscillator's feedback network contained a very tiny low-power filament lamp (which may even have been designed specifically for such purposes, IDK). As the oscillation built up, the lamp would heat up, its resistance would increase, and the feedback factor would be brought down.

I remember that they tried to replace this with other ALC mechanisms but finally decided to stick with that little ole lamp.

 

[AlexB23]

This thread got me thinking. Incandescent light bulbs were soft banned (as in, cannot be sold anymore) in the EU in 2016 and - if my google-fu is to be trusted - last year in the US. If you go to any store selling bulbs, all of them are LED, which makes sense both from many perspectives.* We are soon going to face a generation of students who have never in their life seen an incandescent bulb. Meanwhile, they are typically used as examples in many physics classrooms.

A couple of discussion points:
How should teachers deal with this in the coming years?
Do we need to start introductory classes by explaining what an incandescent bulb is?
What happens with the laboratory experience when physics student labs run out of bulbs (they tend to break) and cannot obtain more?
Should we simply phase out the incandescent bulbs from the curriculum?


* Anecdotally, we were visiting my in-laws in Spain recently with temperatures soaring towards 40 °C. Their second home is sparingly used and therefore was still all incandescent bulbs. It felt slightly absurd to be in Spain in summer, inside with the window blinders shut in almost complete darkness as turning the lights on would heat the house too much. Took a day or two to change all the lights in the house for LEDs.

Guys, you can build incandescent bulbs using graphite pencils and a car battery. But yes, incandescent bulbs were banned in 2023 in the USA. LEDs are more efficient, but if you need incandescent bulbs, old bike lights could work, same with oven lights, as LEDs would overheat in the oven.

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