resistance of incandescent vs halogen

[Plasmah]

Hi all

If I use a Bulb as a current limiter in a circuit would using
a 120v 100 watt halogen bulb act the same as a 120v 100 watt incandescent bulb?

In other words would the halogen bulb act the same as the incandescent bulb providing they where the same specs?

Thanks

 

[audioguru]

A Halogen bulb operates at a higher temperature than an ordinary incandescent bulb so its resistance would be lower when it is cold.

 

[Plasmah]

audioguru

Hehe...

Your always the first one to answer my questions =)

Thanks...

As you can tell I aborted the whole Power resister plan =)
With the feedback you gave me on the subject before. I decided the best and most logical way for what I'm doing is a bulb.

Thanks again

 

[Hero999]

A halogen bulb is a type of incandescant lamp, the only difference is, it's filled with a special gas that enables it to run at higher temperatures.

 

[Sceadwian]

If I'm not mistaken the halogen gas helps the metal that evaporates to re-deposit evenly on the filament, increasing lifetime at higher temperatures.

 

[Dean Huster]

That's correct. It's called the "halogen cycle" and for it to work correctly, the lamp must be operated at normal voltage. I understand that putting them on a dimmer and keeping them operating under-voltage will cause the quartz to blacken prematurely, reducing light output. It isn't so much putting the metal back onto the filament as it is keeping from coating the inside of the envelope.

Dean

 

[justDIY]

all true - but, using the bulb or rather, the filament as a resistor, it doesn't really matter if the envelope becomes clouded or not

 

[Hero999]

Apart from the fact that it won't last as long.

 

[Nigel Goodwin]

Apart from the fact that it won't last as long.

I would agree, it's VERY important to run halogen bulbs at the correct voltage.

 

[Dean Huster]

Of course, that's when you're using them as intended. As for using them far below the glow level, there shouldnt' be any difference. I'd characterize the filament against that of a standard lamp just to see how they compare. Just start with low voltages and measure current each time using a DC supply and then use Ohm's law to calculate the resistance and create a graph for comparison. I can see where using a halogen lamp in place of a standard 150-watt incandescent lamp would have some space-saving advantages. Still, with the smaller envelope, you'll have to watch the heat and mount the thing accordingly.

Dean

 

[Hero999]

A 150W halogen will probably give out as much light as a standard 200W incandescent.

Even so, you're ignoreing the fact that the bulb life is ruduces by running it at a lower voltage as the halogen gas can't return the particles to the filiment and they'll just condense on the bulb's surface making it go black and die.