Electronic Design Software

Why must we warm up a spectrophotometer before using in the lab?

It's a question I need to answer in my lab report. Why do we need to plug in the spectrophotometer and wait for at least 30 minutes before taking the absorbance levels of solutions? I know it has something to do with warming up the lamp and stabilizing the electronics... but I still don't quite get it. Thank you!

Public Comments

1. Older equipment is very sensitive to drift. Temperature variations during warm up would cause your standard solution readings to be different than a stabilized set. Newer digital equipment is so much better. I started out using a Beckman DU. Ask your teacher if he/she has ever seen one of those. Drift in voltage to the bulb was common in old linear power supplies. Drift in voltages to the electronics also was common. Use of temperature sensitive resistors has changed from carbon to metal. Tolerances have gone from 10% to 5% or less with lower tempereature variations. (I worked on that change!). Capacitors have changed from a frequent +/- 20% to 5% in critical circuits.
2. do you go to uc davis? cheater.