BS IEC 60115-4:2022 - Page 4

Fixed resistors for use in electronic equipment. Sectional specification: Power resistors for through hole assembly on circuit boards (THT) or for assembly on chassis | Status: Current

1 Scope This part of IEC 60115 relates to resistors having a rated dissipation typically greater than 1 W up to and including 1 000 W for use in electronic equipment. This document is applicable to fixed power resistors with a maximum surface temperature (MET) higher than the preferred upper category temperature (UCT) of 200 °C.

NOTE Heat sink resistors, i.e. resistors which in their operation depend on being mounted on a dedicated heat sink, owing to their special temperature conditions, are covered by a special sectional specification (under consideration at the time of publication).

These resistors are typically described according to types (different geometric shapes) and styles (different dimensions), and product technology. The resistive element of these resistors is typically

• — protected by a conformal lacquer coating, or
• — cement coating, or
• — vitreous enamel, or
• — a ceramic body, or
• — any other housing, which is to be described in the relevant specification.

The electrical connection of these resistors is typically achieved by means of

• — axial leads for through hole assembly (THT), or
• — vertical or radial leads or punched terminals, or
• — ferrules or lugs for chassis mount, or
• — push on terminals, or
• — screw terminals, or
• — any other termination, which is to be described in the relevant specification.

In special cases, a heat sink can be applicable but not mandatory. The object of this document is to define preferred ratings and characteristics and to select from IEC 60115‑1 the appropriate quality assessment procedures, tests and measuring methods and to give general performance requirements for this type of resistor.

NOTE SMD resistors are covered by IEC 60115‑8, regardless of their dissipation.