The TO-220 package is a three-lead through-hole power outline, 10.11–10.51 mm wide on 2.41–2.67 mm lead pitch, with a metal tab that is electrically live
The TO-218 package is a three-lead through-hole power outline with an exposed, electrically live metal tab — the footprint on a TIP35C, a BUV48A or
The TO-18 package is a hermetic metal can measuring 4.52 to 4.95 mm across the cap, 4.32 to 5.33 mm tall, on a flange of
A TO-126 package body is nominally 11.0 mm tall, 8.0 mm wide and 3.25 mm thick, with a 3.2 mm mounting hole and 2.28 mm
TO-can packages are hermetically sealed metal cylinders with radial leads, still specified where a plastic body cannot go: rad-hard parts, precision references, laser diodes, and
The through-hole vs surface mount decision is usually framed as old against new. That framing is useless at the bench, because most boards need both.
Stud-mount diode packages bolt a rectifier directly into a heat sink or busbar through a threaded stud, with the hex base carrying heat out of
An SPGA package is a pin grid array whose pins sit on two interleaved square grids, each offset from the other by half a pitch
A skinny DIP package is an ordinary dual in-line package whose two lead rows sit 0.300 in (7.62 mm) apart instead of the wide-body 0.600
A SIP package carries all its leads in one row along a single edge, so the body stands on end when the leads go through