- Mar 24, 2011
To measure the current you unscrew the tailcap (the part with the switch), just as you would if you replaced the batteries. But you leave the batteries in the host. You take your DMM, set it to mA or A and make a connection with the leads from the DMM between the battery and the housing. Be careful, this will fire up your laser don't look into the beam! This will give you a reading of the current that flows from your batteries via the driver through the laser diode (and back to your batteries).