How you can calculate resistor size for lasers in parallel for dummiesI have four laser modules obtained from laser pointers. Normally each module runs from three assistive hearing device batteries in series, 1.5 volts per battery 4.5 volts total. It appears like I must limit the amplifiers not always the volts. Each module features its own resistor the onto it is 680. After I appraise the resistance it shows 68 ohms. What should i do in order to get this work ? There has to be a way to merely determine this. Incidentally I've about 40 more laser modules and that i might like for their services all at one time to create say. an unquestionably visible turn signal bulb in my truck or simply a very lighting ton light in my backyard . Basically can determine this the options are endless !Place the models on their own original,laser pointers pen 4.5 volt supply and appraise the current drop over the 68 ohm resistor. I= V/R, so that you can deduce the important current, and also the forward volt drop, since V supply 200mW 532nm Mid-open Kaleidoscopic Green Laser Pointer Pen with 2AAA Battery Vdropped = Vlaser. Used to do the information with 3 assistive hearing device batteries slightly decharged ( 3.96 V ) after i measured over the resister I acquired a current drop of just one , after i used some slightly more recent batteries ( 4.40 V ) I acquired a current drop of just one.26 ? Basically have 3 Volts 1Vdiode = 2 ohm resister? I had been curious and so i put 2 D batteries together, Green Laser Pointer connected these to the laser ( using its original 68 ohm resistor ) and also the current drop was the laser didn't work. I even side stepped the resistor and also the laser Did not illuminate or burn up. I attempted exactly the same with 4 AA batteries No light and didn't burn up ? So why with 3 assistive hearing device batteries the laser will sensational looking nothing using the D or AA batteries. Should not I a minimum of have the ability to result in the laser light or burn it using the bigger batteries? For Prison Your right while my neighbors are utilized to my projects I am unsure the relaxation around the globe could be .