Triode, the full name should be semiconductor triode, also known as bipolar transistor, crystal triode, is a semiconductor device that controls current. Its function is to amplify the weak signal into an electrical signal with a larger amplitude value, and it is also used as a non-contact switch.
The triode is one of the basic components of semiconductors. It has the function of current amplification and is the core component of electronic circuits. The triode is made on a semiconductor substrate with two PN junctions that are very close to each other. The two PN junctions divide the whole semiconductor into three parts. The middle part is the base area, and the two sides are the emitter area and the collector area. The arrangement is PNP And NPN two kinds.