Linear Systems's Flame rod sensor senses the flame using flame detection rectification technique. The Amplifier provides a voltage for the Flame Electrode. The flame electrode is immersed in flame to sensed. The current thus generated by the flow of electrons through the flame to the ground is detected by the controller for presence of flame. The sensor senses only the burning flame and completely insensitive to visible light and refractory glows. It is best suited for sensing flame in Gas fired burners.