Riedon’s thin film resistors are offered in power ratings of 20W, 30W, 50W, 100W, and 140W depending on what the specific packaging is. Resistance values can be manufactured in any resistance value from 0.02 Ω up to 51 kΩ. With regards to a heat sink, an aluminum alloy board is often used. Looking at Figure 3 shown here, for a heat sink of 2.8°C/W, the temperature rise of the resistance film and the copper tab have different slopes. Subtracting the two curves of the graph provides the thermal resistance of the resistor.