HeNe ballast resistor question....

[GooeyGus]

So what is the purpose of the big ballast resistor on HeNe lasers? Is it just to limit the current going to the tube or is there some other purpose I'm missing here??

 

[FrothyChimp]

Yep, you need something to limit the current when the gas ionizes or it'll keep drawing more and more current because the ionized gas looks like short.

 

[Cyparagon]

While we're on the subject, why aren't HeNe lasers considered ion lasers if the lasing medium is ionized?

 

[daguin]

While we're on the subject, why aren't HeNe lasers considered ion lasers if the lasing medium is ionized?

They are. Check out the many articles referring to them as ion lasers

http://www.google.com/search?client...&hl=en&q="helium+neon+ion"&btnG=Google+Search

Peace,
dave

 

[heruursciences]

A 5W 85K to 105K power resistor should work fine