Bulb/ battery size combo.

[eebowler]

As an example, the Bright Star Responder is a 4AA flashlight which uses a PR based bulb. Quickbeam's review stated that other PR based bulbs can be used in the flashlight.

My question is this: If I use a bulb designed for a 4D flashlight in the Responder (4AA), will it be any duller than it would be in the 4D? General quality etc aside,(both bulbs being xenon) will it drain the batteries faster than the original Bright Star bulb? Should I expect the brightness vs time graphs for both bulbs in the responder flashlght to be about the same shape?

This question extends to other bulb battery combinations as well. eg maglite 2D bulb with a 2AA flashlight or a maglite 2AA bulb with 2D size cells.

Should I be asking: Are incandescent bulbs current driven or voltage driven?

Thank you for your inputs.

 

[jayflash]

Incans are voltage sensitive. Enough source current must be available to maintain proper voltage. Light output will drop with less volts.

 

[eebowler]

Ok, so if incandescent are soley voltage dependant, then, the size of battery wouldn't matter, and would only determine how long the bulb maintains a certain brightness?

This would suggest that even though the maglite bulb was designed for use with 4D cells, it will perform the same as the Bright Star bulb designed for 4AA cells, or vise versa?

 

[Ginseng]

No. That's not correct either. Jay stated that incans are voltage driven devices which seek to pull the current they need to maintain their operating voltage. This means that they are very dependent on the power source used to drive them. For example, in the extreme case of the 4.8V WA01183 bulb, it will try to pull 4.85-5A of current. Use this with 4xAA, AA, C or D alkies and you'll barely get the filament to glow. Current will be depressed and so will the voltage. Run them on good nicads and you'll get a very bright bulb.

In general, smaller cells within a same chemistry (nicad, alkaline, nimh) and type (high capacity, high current, high temperature) will provide less current capability. Thus, a bulb designed specifically for 4D may be visibly less bright with 4AA.

Wilkey

 

[eebowler]

Thank you Ginseng and jayflash for your help. It makes more sense now.