This PZEM-004T V4 is a multi-function AC power monitor module used for measuring the AC voltage, current, active power, frequency, power factor and active energy via a non-invasive Current Transformer(CT) and TTL serial communication.
The MA112AS16 is a USB to UART controllers, developed by Megawin Technology Co. At its core, this device functions as a bridge between USB interfaces, presenting itself as a standard virtual COM port.
The CH340 is a popular IC that is a bidirectional USB to Serial converter IC, used to convert USB signals into UART, which can be used to communicate with microcontrollers.