What is component 6 in figure T-2?

In Figure T-2, component 6 is the schematic symbol for a capacitor. The basic capacitor symbol is drawn as two parallel lines with a gap between them, directly illustrating its physical construction of two conductive plates separated by a dielectric insulator. Some capacitor symbols feature one straight line and one curved line, which indicates it is a polarized capacitor (such as an electrolytic type) that must be installed in a specific direction. This symbol differs from a resistor, which is a zigzag line, and an inductor, which is drawn as a series of coiled loops.