Which connector replaced the mini USB and has gained popularity with smartphones?

The micro USB connector is the answer because it was specifically designed to be a smaller, more versatile connector that fits the needs of modern smartphones and other portable devices. It became widely adopted due to its compact size, ease of use, and the ability to support faster data transfer rates and charging compared to its predecessor, the mini USB.

Micro USB connectors are reversible, unlike standard USB connectors, which adds to their convenience for users. This connector demonstrated a significant improvement in usability and efficiency, especially as device manufacturers began prioritizing thinner designs.

The other options are not as prevalent for mainstream smartphones. The standard USB connector is larger and not suitable for compact devices. The Thunderbolt connector, while high-speed and capable of transmitting data and power, is typically used in more specialized applications like computers rather than for general smartphone use. The Lightning connector, developed by Apple, is specific to Apple devices and does not apply to the broader smartphone market, which primarily uses micro USB and USB-C connectors. Thus, micro USB stands out as the industry standard that replaced mini USB in smartphones.