Ballast
- give out a little bit of RF interference, blocks cell phone comm.
- cannot be combined with passive (synched)
- emit a little noise
-older technology (original)
Passive
-can be synched
-do not require a ballast between the lighthead and the power source (in the case of talons, the ballast is built in, but for ballast lightheads you need the ballast or they don't work.
basically the way the ballast works is that it steps up the voltage from 12v to 18v, which is what the ballast requiring lightheads are built to function on. therefore a standard 12v connection is just not enough power for the ballast lighthead if it is missing the ballast component.
hpd can add what ever i missed