SCR Package Style

TO-208 Package

SCR Package TO-208 Case style, Bolt Mount Package

TO-208 SCR Package Outline and Dimensions
TO-208 SCR, Stud-Mount Component Package

The TO-208 package is a 3-terminal Bolt mounted device used for FETs, transistors or in the example a high power Silicon Controlled Rectifier [SCR], as well as for other applications. Other 3-terminal semiconductors may also use this case style, but the SCR pin locations are shown in the graphic.

The Anode or bolt portion of the component body should be attached to a Printed Wiring Board [PWB] or metal heat sink while the opposite terminals of the component [Cathode and Gate] require lead wires to attach to the circuit.

The Anode of the package should be mounted to a heat sink if possible, as in a larger copper pad on the PWB or metal plate used to dissipate heat. Because of the length and resulting thermal resistance the lead wires attached to either the Gate or Cathode will not be able to dissipate any heat from the package. The stud, or terminal 3 as indicated in the graphic, is threaded. The size of the threaded stud and the number of threads per inch changes depending on the package.

A number of Thyristors [SCR] use this package style including; 2N682, 2N683, 2N685, 2N686, 2N687, 2N688, 2N689, 2N690, 2N691, 2N692, 2N692A, and 2N5206

Transistor Package
Stud Hex Base Family
Solid Terminals

Schematic symbol for an SCR with labeled pins
SCR Symbol

Related Semiconductor Topics:
Types of Diode cases
Diode Derating Guidelines
Diode Derating Curves
Diode Manufacturers
SCR Manufacturers
Thyristor Manufacturers

Types of Transistor cases
Transistor Derating Guidelines

SCR Packages Styles;
TO-5, TO-39, TO-64, TO-66,
TO-92, TO-126, TO-202

PC motherboard

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Modified 6/13/15
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