· Rich Dumas
Modern slot cars with lights use LEDs for then most part and those are fussy about the voltage they are fed. White and blue LEDs run at 3.5 volts, red LEDs run at 2 volts and even a half volt too much will greatly reduce their life. LEDs do not have filaments, so they are tolerent of rapid changes in voltage. With many lighted slot cars dropping resistors are used and those are sized based on the maximum track voltage. It appears that SCX tracks use a slightly lower voltage than other makes so their lights can burn out when you run the cars on another make of track. A more sophisticated lighting system would include a voltage regulator, which can cope with different track voltages.