Discrete devices are widely used in fields such as consumer electronics, computers and peripherals, network communication, automotive electronics, LED displays, etc. Discrete devices are one of the two major branches in the semiconductor industry, the other being integrated circuits. Discrete power devices include semiconductor diodes such as germanium diodes, silicon diodes, compound diodes, etc; Semiconductor transistor: germanium transistor, silicon transistor, compound transistor, etc; Special devices and sensors; Sensitive devices: pressure sensitive devices, magnetic sensitive devices (including Hall devices and Hall circuits), gas sensitive devices, humidity sensitive devices, ion sensitive devices, sound sensitive devices, radiation sensitive devices, biological sensitive devices, electrostatic sensitive devices, etc; The assembled piezoelectric crystal is similar to a semiconductor device;