Triode, the full name should be semiconductor triode, also known as bipolar transistor, transistor, 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, which has the function of current amplification and is the core component of electronic circuits. The triode is made of two PN junctions that are very close to each other on a semiconductor substrate. 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.