Hi, newby here, hope I can get some help on this question. I have a project that requires me to use a standard 9 LED torch head, normally running on 4.5 volts (three AA batteries) My project needs me to use 12 volt batteries to supply a control box and finally the 'torch heads' a distance away (miniature railway signalling). To provide the voltage needed at the final point I intended running the 12 volts through a Voltage Regulator almost at the final stage of wiring, that delivered 5 volts from the voltage which starts out at 12 volts, and obviously drops a little due to the length of wiring. If I leave the voltage at 5 volts it damages the 'torch heads LED's' so what do I need to do the drop the other half a volt to provide the final 4.5 volts. Not sure though what the impedance of the torch heads are.