Silicon-coated power resistors

The HTA Series of silicon cement coated power resistors from VTM (UK) offers a cost-competitive alternative to vitreous enamel coated types over the 2.5-12W power range.

The HTA Series of silicon cement coated power resistors from VTM (UK) offers a cost-competitive alternative to vitreous enamel coated types over the 2.5-12W power range.

The range is available with resistance values of 0.1ohm to 100kohm in power ratings of 2.5, 6, 9 and 12W (at 70C), and with body sizes that match the industry standards.

Vitreous enamelled resistors were introduced at a time when alternative directly applied coatings could not withstand the thermal stresses caused by the resistors' high body temperatures.

However, although vitreous enamel coated resistors can tolerate high body temperatures, the insulation properties of the resistor decrease with temperature.

In addition, the price of these resistors tends to be high, mainly due to the additional labour required to clean the leads after the firing of the enamel.

In recent years, improvements in silicon coating materials have made them a viable alternative - with the added benefit of a cost advantage of up to 40%.

An additional advantage of these devices is that Ayrton-Perry windings can be used to give low-inductance resistors within the same package dimensions.

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