Transistor Case Packages

TO-78 Package

Transistor Can Package TO-78 Case style, Metal Can

TO-78 Metal Package Dimensions
TO-78 Metal Can

The TO-78 package is a 8 pin device in a metal can. Note that a 6-pin package is shown, with two pins omitted. Pin locations 4 and 8 do not have a terminal attached.
Example configurations include a Dual Transistor package, [with both a NPN & PNP transistors] shown below and an Opto-coupler shown to the left.

Of course many other semiconductor configurations are possible than the ones shown here. The devices listed here are just meant to be possible examples.

Editor note; this package will hold any number of pins as long as they reside on the .200 inch pin circle, as shown in the diagram. This particular example has 6 pins, with terminals 4 and 8 missing, although they could be present on another package variant. Some designers may not use this package in there designs because the package is a through-hole part, although many companies still use through-hole components. Mixing through-hole components with surface mount parts adds to the complexity and cost of board manufacturing, so once some parts move to surface mount parts, all the parts used begin to be surface mount components.

Package type; through-hole device
8 Axial Leads, .200 Pin Circle

4N47 Opto-Coupler Schematic, TO-78, Pin-out and Lead Identification
TO-78 Opto-Coupler

Solid State Devices; 4N47, 4N48, 4N49

Types of Transistor cases.
Guideline to Derating Transistor.
Definition of Transistor Terms.
Manufacturers of FETs and BJTs

Dual PNP Transistor;

PC motherboard

Distributor rolodex Electronic Components Electronic Equipment EDA CDROM Software Engineering Standards, BOB card Cabled Computer Bus Electronic Engineering Design Table Conversion DB9-to-DB25.
DistributorsComponents Equipment Software Standards Buses Design Reference
Modified 6/13/15
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