MECHANICAL PARAMETERS

Explanation of Dimension Code

Each Resistor Type is assigned a 4 digit code, the first 2 digits give the nominal Active Diameter (D) in mm and the last 2 digits give the nominal Active Length (L) of the Resistor in mm. From this information the Volume of Active Material (v) may be determined.

Construction

The Gold Plated Brass terminations are attached to the Copper metallised contact on the Resistor body opposing flat surfaces, with high melting point solder. This permits reliable short time operation at temperatures up to 200 °C.

Coating

The UL94 V-0 approved epoxy resin coating is applied by fluidised bed technique. The coating finish is hard, smooth and has good appearance to harmonise with other electronic components.

If this range of Resistors experience surface temperatures regularly in excess of 150 °C, the coating will tend to degrade slightly, becoming darker. Though unsightly, performance is not compromised.

Whilst the coating can reduce the rate of moisture ingress, it is not impervious to liquids.

Terminations / Soldering

The Gold Plated Brass termination pins are 1.5mm wide by 0.4mm thick with the spring pin format designed to ensure stability during PCB assembly. HVR recommend, as a minimum, PCB mounting holes of 2.0mm Diameter.

Soldering is permissible with mildly activated fluxed solders with liquidous properties less than 230 °C.

Coefficient of Linear Expansion

In the range +4 x 10^-6 to +10 x 10^-6 per °C depending on material Resistivity.