Now that the importance of heat sinks has been stated, an example will be given on the impact that heat sinks can have on the heat dissipation and temperature of applications. For the remainder of this product training presentation, let one assume that an application is being developed using a transistor housed in a TO-220 package, the switching and conduction losses of the transistor equate to a power dissipation of 2.78W, and the ambient operating temperature is not expected to exceed 50°C. The first step is to gather and understand all of the thermal impedances that stand in the way of the 2.78W from being dissipated into the ambient air. If those Watts cannot dissipate efficiently, the junction temperature inside the TO-220 package will rise beyond the recommended operating conditions (typically 125°C for silicon).