Pulse start lamps - HPS and Metal Halide

[peter d]

Why do pulse start HID lamps contain a small metal disk at the base of the lamp connected to one of the electrodes? This metal disk sits directly opposed to a metallic coating on the inside of the lamp.

I am guessing this is a crude capacitor of sorts, but what purpose does it serve in the lamp function? Obviously it serves a useful function or else it wouldn't be there.

 

[peter d]

Surely someone knows what the purpose of this device is among the vast brainpower here. I need to be able to sleep tonight.

 

[iwire]

I think that is where the bright stuff is stored when the lamp is off.

 

[peter d]

I think that is where the bright stuff is stored when the lamp is off.

That's the best you can do?

 

[gar]

101214-1955 EST

Try this google search
hid lamps and getter

One result is
http://iopscience.iop.org/0022-3727/38/17/S08

You can probably find better references. Search for
vacuum tube getter
For maybe a better discussion on getters.

.

 

[mikeames]

I am guessing this is a crude capacitor of sorts, but what purpose does it serve in the lamp function? Obviously it serves a useful function or else it wouldn't be there.

I had the same thought but never considered asking.

 

[iwire]

That's the best you can do?

Yes .......................

 

[peter d]

Yes .......................

I'm disappointed Bob. Someone with such a massive brain should do much better.

 

[iwire]

You are confusing ego with brain power.

 

[peter d]

You are confusing ego with brain power.

I'm not sure why you have such a big ego. Have you looked in the mirror lately?!?!