Does my flashlight have a voltage regulator?

I have a PT Impact II and i coupled it with 4 Sanyo 800mAh AAA batts.
Now the light seem very much dimmer and i'm wondering whether my flashlight has a voltage regulator allowing the flashlight to continue producing light. I guess the batts are gonna be fully discharged soon.

I am pretty sure the impact just uses a resistor to get the voltage down from 6v (4AA alkaline) to the 4.5-5v the LED's want. So since your starting with 4.8v (4AA NiMH) it is dropping to about 4v, a bit lower then what the LED's like to see. It should run MUCH longer at that level using NiMH's, but be a bit dimmer from the start.

Thanks Brock! I got it...initially i thought the regulator allows the flashlight to continue giving out light(though dimmer) but later on, i found out that the voltage regulator actually helpes the flashlight to continue producing light at the same brightness though the batteries are going to be depleted.
A bit of confusion on my side...haha

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Brock said:
I am pretty sure the impact just uses a resistor to get the voltage down from 6v (4AA alkaline) to the 4.5-5v the LED's want.

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Yes, the Impact II uses a 22.5 ohm resistor (at least mine does) to *limit the current* (not 'lower the voltage').

In fact it's the only 'part' there. The circuit is battery plus, through the resistor, the LED, the switch to the minus (in that order for 'conventional current', the other way about for electron flow).

This means that the light output drops as the battery voltage goes down. It starts out on NiMH at the same level as 'half used' alkalines, fairly dim in this case.

So, "No, your flashlight has no regulator of any sort, only a simple series resistor to help limit current". And you'd want a current regulator anyway.

Doug Owen