Yaregelun When using 3.3V operating voltage, CH340 chip V3 pin should be connected with the VCC pin, while the external input 3.3V power supply, and with the CH340 chip connected to other circuits can not exceed the operating voltage of 3.3V. Module defaults to 5V operating voltage, the chip voltage from the USB interface, if you want to change to 3.3V operating voltage, you need to back the module 5V, 3.3V working voltage selection point to switch to the middle point and another point shorted. At this point need to VCC feet to the module input 3.3V power supply, the module can work.
Product Features
1) Chip: CH340C
2) Operating voltage: 5V or 3.3V
3) Data bits: 5bit, 6Bit, 7bit, 8bit
4) stop bits: 1,2
5) Verification: odd, even, no, Mark, space
6) Transmission rate: 50 ~ 2MHz
7) Current limiting fuse: 500ma
8) : xp, win7,8,10
9) Operating temperature: -40 ° ~ 85 °
10) Size: 10.4mmx28.5mm
The appearance and color of different batches of products may be different, which not affect the use.
Color: green
Material: PCB

Package Contents:
5 x Module With Cable

Only the above package content, other products are not included.
Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.