Stud-mounted SCR mechanical/electrical interface In a stud-mounted SCR package, how is the stud normally connected with respect to the heat sink?

Introduction / Context:
Stud-mounted SCRs are designed for direct mounting to a heat sink through the threaded stud. The stud is typically tied to one device terminal (commonly the cathode), providing both heat removal and an electrical connection through the mounting hardware.

Given Data / Assumptions:

• Standard stud package per common SCR datasheets.
• Heat sink is metallic and grounded or appropriately connected.
• No special insulating bushings are installed (unless explicitly required by design).

Concept / Approach:

The stud forms part of the thermal path and also serves as an electrical terminal. Therefore, by default the stud is in electrical and thermal contact with the heat sink. If electrical isolation is required, insulating hardware and pads are added to break the conductive path, but that is not the default arrangement.

Step-by-Step Solution:

Verification / Alternative check:

Package drawings label the stud terminal (often cathode) and indicate torque specifications for thermal/electrical integrity.

Why Other Options Are Wrong:

• “Thermal only” ignores the metal-to-metal electrical path.
• “Insulated” is only true if special insulating kits are used.
• “Either/or” is ambiguous and not representative of the default package use.

Common Pitfalls:

Mounting without understanding which terminal is the stud can cause unintended grounding or shorts. Always follow datasheet polarity and isolation guidance.

Final Answer:

in electrical and thermal contact with heat sink