> I'm considering using an incandescent light bulb as a current limiter in a
> circuit, but having trouble finding voltage versus current data for light
> bulbs. All my Google searches turn up consumer info on people that want to
> sell me light bulbs. Using the term ballast turns up stuff on fluorescent
> lamps. Using constant current turns up stuff on LEDs. So, anyone know
> where such data may exist?


Although such data does exist for "ballast" type bulbs, it does not exist
for incandescent bulbs since that isn't the intended purpose.

I used incandescent bulbs as (high frequency driver)speaker protection for
public address systems many years ago. I had to do the testing myself. As
I recall(and it's been many years), the nonlinear portion happens before
and just at the beginning of any "glow". By the time you see a little
orange in the red the bulb has become a resistor. And the threshold
current is in the same order of magnitude as the operating current, and I
think a little bit lower. So if you have a 12 volt, 1 amp bulb, the
threshold current might be somewhere around 1/2 amp, and cold resistance
is probably 1/2 ohm. But as I say, it's been many years. I was using
brakelight and reverse light automotive bulbs.

Do some tests, it's fun!

Cheerful regards,

Bob


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