Bead, Filter, Capacitors, communication Interface Chip, UART, 485/232, Connectors, Crystal Oscillator, Oscillator, Resonator, Diodes, Inductors/Coils/Transformers, Key/Switch, Optocoupler, LED, Digital Tube, Photoelectric Device, Power Supply Chip, Resistors, Sensors, Single Chip Microcomputer, Microcontroller, Triode, MOS Tube, Transistor.