TO-3

Overview
TO-3 refers to a kind of integrated circuit package, most often used with older-style power transistors and regulators.

Identification
It appears as a metal can of about 25mm (1") in diameter, with a flange.

Device identification is by means of markings on the top of the can.

Application Notes
Intended for higher current applications, the TO-3 package can be mounted directly to heatsinks or metal cases.

Note: that the case of the TO-3 package often functions as one of the outputs, not necessarily ground. In this case, you may choose to isolate the package from the case or heatsink. Kits to do so are commonly available.