In PCB (Printed Circuit Board) design and manufacturing, "Covered PTH" and "Exposed PTH" are terms used to refer to different methods of handling plated through holes (PTHs) during the solder mask application process.

1. Covered PTH:

   • "Covered PTH" translates to "Covered PTH" in English.
   • It refers to the process of applying solder mask over the entire PCB surface, including covering the plated through holes with solder mask material.
   • Covered PTHs are not exposed, and this helps prevent solder from flowing down the holes during component soldering, reducing the risk of solder bridging and short circuits.
   • The solder mask covers both the top and bottom sides of the PCB, effectively "covering" the plated through holes.

2. Exposed PTH:

   • "Exposed PTH" translates to "Exposed PTH" in English.
   • It refers to the process of leaving the plated through holes uncovered by solder mask, so they remain exposed.
   • Exposed PTHs are usually required for specific applications, such as press-fit connectors or certain high-current applications where direct soldering of components or conductive materials is needed through the holes.
   • By leaving the holes open, components can be inserted through the holes and soldered on the opposite side, creating a secure and reliable connection.

In summary, Covered PTH involves covering the plated through holes with solder mask material to protect them during soldering, while Exposed PTH leaves the holes uncovered, making them accessible for specialized applications that require direct soldering or press-fit connections through the holes.