The manufacturing process of a platinum RTD (Pt-RTD) element begins with a thin film of pure platinum deposited onto a high purity aluminum oxide substrate. To create an electrical circuit, a pattern is etched onto the RTD film, after which the circuit is laser trimmed to the desired electrical resistance value. Once the trimming process is complete, lead wires are attached to the element and a coating is applied to protect both the platinum film and the lead wire connections. The use of platinum provides a high positive and nearly linear temperature coefficient and limits the susceptibility of the element to corrosion and/or oxidation.