VR Optimal Bulb Voltage Setting

[davo123]

If you were to set a voltage regulator output to run a 3.6 volt krypton bulb, would you use a higher or lower voltage than the recommedned 3.6 volt setting. A higher voltage (+3.7 volts) would offer a brighter bulb, but may shorten the life of the bulb. On the other hand, a lower voltage (-3.5 volts) would give the bulb a dimmer light, but would extend the life of the bulb. Has anyone any information on the exact voltage a bulb should be set? Test info, or bulb manufacturer info would be great. I can't find a bulb manufacturer that references this. Thanks!

 

[Jonathan]

There is no exact right value for a particular bulb. Instead picking the operating voltage is a design tradeoff between total light output (or efficiency), and bulb life.

Basically ask yourself: is the lamp life too short. If it isn't, then you have room to up the applied voltage, getting more light and greater efficiency.

If you go to the Welch Allyn halogen web pageand then select 'technical data' you will find a number of papers on halogen lamp properties. The 'electrical characteristics' paper is particularly relevant to your question. It provides the approximations that will let you see what happens with different voltage levels.

The great thing about using a voltage regulator is that you are no longer tied to matching the lamp to the battery to set operating voltage. If you want to run with 3.8 or 3.9 volts, you can do so.

Regards,
Jonathan Edelson