avatar: J.Bloggs
7 posts
Replied to J.Bloggs post on August 29th, 2012

I have a PerkinElmer AA200.  The Cd Lamp is a PerkinElmer Luminaits.

It states on the lamp that it operates from 4 amps to max 8amps.

Now when I was fiddling around I found out that the Cd lamp had been running at 8amps since it had been installed.

I reduced this to 4 amps and of course the intensity dropped.  The results of a QC sample and ILCP readings were more noisy but the average of 3 reads of 3 were more accurate.

Anyway, what is the expected effect of over and under amps, apart from intensity?

Replied to J.Bloggs post on September 25th, 2012

Hello J. Bloggs,

PerkinElmer lamps have a recommended operational current and a max current on the label. The operating current is not a minimum energy, just a recommended amperage to use. Some lamps may operate better above the recommended operating current, some may actually operate better slightly under the recommended operating current.

In general operating at higher current will produce more intensity from the lamp but also usually results in more noise, which means you may not get a better detection limit despite the increased intensity, and a shortened lamp lifetime. Though as a lamp ages and gets weaker you may be able to get a few more hours of use out of it by raising the current. I recommend keeping the current low as long as you can meet the characteristic concentration to increase lamp lifetime.