The resistance of USB socket interfaces is generally very small, mainly reflected in the following aspects:
- Contact Resistance
The USB standard has clear requirements for contact resistance:
·Maximum not exceeding 30 milliohms (m Ω)
·High quality USB connectors (such as USB 3.0 or industrial grade USB) typically have a contact resistance of less than 10 m Ω. - Wire and solder joint resistance
·The wire resistance in USB connections is generally very small, for example, a one meter long USB cable has a wire resistance of about 50-100 m Ω (depending on the thickness of the wire).
If the welding process is good, the resistance should be between 1-5 m Ω. - Overall resistance estimation
The total resistance passband from the US8 socket to the connecting wire, plug, and the entire device circuit is within 100-200 m Ω. If it exceeds this range, it may affect voltage transmission, especially in high current scenarios such as USB PD fast charging.