Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives Magazine Sponsor RF Cafe Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Alliance Test Equipment Centric RF Empower RF ISOTEC Reactel RF Connector Technology San Francisco Circuits Anritsu Amplifier Solutions Anatech Electronics Axiom Test Equipment Conduct RF Copper Mountain Technologies Exodus Advanced Communications Innovative Power Products KR Filters LadyBug Technologies Rigol TotalTemp Technologies Werbel Microwave Windfreak Technologies Wireless Telecom Group Withwave RF Cafe Software Resources Vintage Magazines RF Cafe Software WhoIs entry for RF Cafe.com Thank you for visiting RF Cafe!
TotalTemp Technologies (Thermal Platforms) - RF Cafe

Temwell Filters


Please Support RF Cafe by purchasing my  ridiculously low-priced products, all of which I created.

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

Windfreak Technologies Frequency Synthesizers - RF Cafe

Package Outlines - Transistor Outline (TO)

TO-3  package outline - RF Cafe

3-Pin Transistor Outline (TO-3) Package 

TO-8  package outline - RF Cafe

8-Pin Transistor Outline (TO-8) Package 

TO-8B/LP  package outline - RF Cafe

8-Pint Transistor Outline (TO-8B/LP) Package 

TO-92  package outline - RF Cafe

3-Pin Transistor Outline (TO-92) Package 

TO-202  package outline - RF Cafe

3-Pin Transistor Outline (TO-202) Package 

TO-220  package outline - RF Cafe

3-Pin Transistor Outline (TO-220) Package 

TO-226  package outline - RF Cafe

3-Pin Transistor Outline (TO-226) Package 

 - See Full List - 

Transistor Outline (TO) Package - RF CafeTransistor Outline (TO) Package

The term "TO" in transistor outline package (TO package) refers to a type of metal can package used for housing discrete electronic components, including transistors. The TO (Transistor Outline) series of metal can and encapsulated plastic packages has been around since the 1950s, when the first commercial transistors became available. Over time, plastic was substituted for some applications, and the applications expanded to include circuits like voltage regulators, photosensors. TO packages are known for their distinctive metal can shape, which provides thermal and mechanical benefits. Here are some key features and common variations of TO transistor outline packages:

  • Metal Can Shape: TO packages are typically cylindrical metal cans. They are often made of materials like aluminum or steel, which provide good thermal conductivity and protection for the enclosed semiconductor device.
  • Pin Configuration: TO packages have two or more pins that protrude from the bottom of the can. The number and arrangement of pins depend on the specific TO package variant.
  • Variants: There are several variants of TO packages, and the numbering scheme typically indicates the package's physical dimensions and pin configuration. Common TO package variants include TO-92, TO-220, TO-247, TO-3, and TO-18, among others. Each variant has its own size, pin arrangement, and power handling capabilities.
  • TO-92: A small, three-pin package commonly used for small-signal transistors. TO-220: Larger package suitable for medium-power transistors and voltage regulators.
  • TO-247: Larger and more robust package often used for high-power transistors and power semiconductors.
  • TO-3: A larger metal can package primarily used for high-power and high-voltage transistors.
  • TO-18: A smaller metal can package used for various discrete components, including transistors and photodiodes.
  • Heat Dissipation: TO packages are known for their good thermal properties. The metal can acts as a heat sink, helping to dissipate heat generated by the enclosed transistor. This makes them suitable for applications where heat management is crucial.
  • Mounting: TO packages are designed to be mounted directly onto a printed circuit board (PCB) or a heat sink using screws or clips. The metal body provides mechanical stability and can enhance thermal performance when mounted to a heat sink.
  • Sealing: TO packages are typically hermetically sealed, which means they are air-tight to protect the enclosed semiconductor component from moisture and environmental factors. This sealing enhances the long-term reliability of the component.
  • Applications: TO packages are commonly used for a wide range of discrete semiconductor devices, including bipolar junction transistors (BJTs), power transistors, voltage regulators, and other components requiring good thermal performance and mechanical durability.
  • Obsolete in Some Applications: While TO packages are still used in various applications, they have been partially replaced by surface-mount packages (SMT) in modern electronics, especially for smaller and more compact devices where space is a critical consideration.

TO-237  package outline - RF Cafe

3-Pin Transistor Outline (TO-237) Package 

TO-263  package outline - RF Cafe

3-Pin Transistor Outline (TO-263) Package 

Windfreak Technologies Frequency Synthesizers - RF Cafe
ConductRF Phased Matched RF Cables - RF Cafe

Anritsu Test Equipment - RF Cafe

withwave microwave devices - RF Cafe