Front light circuit? Choosing a resistor...

[circahasfallen]

Hello all!

I am doing a project with my GBA and it runs off 2 AA batteries. What I am trying to do is add a front light to it. The front light runs well at 3v but while playing old GB games the system bumps up the voltage to 5v which in turn burns out the front light. The circuit I want to create is batteries to switch (3v-5v) then from switch to resistor (regulating at 3v-3.5v) then to the front light. How would I go about building this? I do solder PCBs and that is no problem, but I need to know how I can do this so I can turn the front light on and off and not blow the light. Any suggestions or help would be appreciated!

 

[Diver300]

Buy a low-dropout 3 V regulator and run the light through that. No switching required. Any idea how much current the light takes?

 

[MikeMl]

I'll bet the "front light" is a LED, missing the required current-limiting resistor. Put a 47 Ohm resistor in series with the LED. DONE!

 

[circahasfallen]

**broken link removed** That is the front light. Sorry I forgot to mention it is most likely LED as it goes in front of an LCD screen to light it, hence "front light." Is there any easy way I can see what the current or amps are? Sorry about all the questions, I'm new to the building aspect of electronics.