TO-3

In electronics, TO-3 is a designation for a standardized metal semiconductor package used for power semiconductors, including transistors, silicon controlled rectifiers, and, integrated circuits. TO stands for "Transistor Outline" and relates to a series of technical drawings produced by JEDEC. The TO-3 case has a flat surface which can be attached to a heatsink, normally via a thermally conductive but electrically insulating washer. The design originated at Motorola around 1955. The lead spacing was originally intended to allow plugging the device into a then-common tube socket.

TO-3

In electronics, TO-3 is a designation for a standardized metal semiconductor package used for power semiconductors, including transistors, silicon controlled rectifiers, and, integrated circuits. TO stands for "Transistor Outline" and relates to a series of technical drawings produced by JEDEC. The TO-3 case has a flat surface which can be attached to a heatsink, normally via a thermally conductive but electrically insulating washer. The design originated at Motorola around 1955. The lead spacing was originally intended to allow plugging the device into a then-common tube socket.