Thin Film Platinum Resistance Temperature Detectors (RTD) consist of a very thin layer of Platinum deposited onto an Aluminum Oxide ceramic substrate. The Platinum film is laser etched into a grid to form a resistive circuit and coated with a thin layer of glass. Larger lead wires are attached to the film and the attachment point is cemented in place with glass. This type of construction has a quick response time due to the low mass and large surface area. The Platinum film used allows for high repeatability, stability and linearity at a very affordable cost.