What is component 8 in figure T-2?

Component 8 in Figure T-2 features a standard diode symbol—a triangle pointing toward a straight vertical line—but with the crucial addition of two small arrows pointing away from the symbol. These outward arrows signify light being emitted, identifying the component as a Light Emitting Diode (LED). The base diode symbol indicates that current only flows in one direction. The added outward arrows are the universal schematic method for showing that a component radiates energy outward (in this case, visible light). If the arrows were pointing toward the triangle instead, it would represent a photodiode (which receives light). It is not a resistor or inductor, which use zig-zag or coiled lines, respectively.