A TO-92 package. (Enlarge)

The TO-92 package is a low cost housing used for small-signal semiconductor components...

• A TO-92 has three connectors.
• The TO-92 package is made of plastic.

A TO-92 component can dissipate very little heat and can therefore easily "burn out".

A TO-92 component does not fit on your breadboard straight away. For this you need to carefully bend the connectors with pliers.

Examples of TO-92 components...

• Transistors BC547, BC557, BC516, BC517

A TO-220 package. (Enlarge)

The TO-220 package is used in numerous transistors and integrated circuits...

• A TO-220 has three connectors.
• A TO-220 package has a metal latch for attaching a heat sink.

A TO-220 with a heat sink can dissipate heat of several Watts, significantly more than a TO-92 package.

Examples of TO-220 components...

• Voltage regulators 7805, 7809