Originally Posted by
mtrain
In your picture it looks like you have the two flashlight batteries in Series , not Parallel . In Series , they will put 3 volts into your glowhead and instantly burn it out resulting in the no start condition your presently experiencing . If they are in Series , change the connection of the cells to a Parallel configuration , replace the burned out glowhead , and you should be good to go . PS , the wiring of either + or - to either glowhead connection does not matter , the circuit will work just fine since the little piece of Nichrome wire is not a polarity sensitive component like a Diode or Transistor is . It'll still get hot no matter which way you feed it 1 1/2 Volts ....