Four layer diode

from Wikipedia, the free encyclopedia
Shockley Diode:
a. physical structure of the semiconductor layers,
b. Equivalent circuit diagram ,
c. Circuit symbol
Four-layer diode 2Н102Г

The four-layer diode , also known as a dinistor or a Shockley diode (after the physicist William B. Shockley ), is a silicon semiconductor component with four semiconductor zones. The first four-layer diodes were manufactured by Shockley Semiconductor Laboratory in the late 1950s and were among the first semiconductor components made from silicon .

Today it has been replaced by other semiconductor components , in particular the diac , and is no longer of economic importance.

The Shockley diode is not to be confused with the Schottky diode .

function

The function of the four-layer diode is similar to a thyristor with a gate not connected. The component consists of four differently doped semiconductor layers and three pn junctions , as shown in the figure under a. shown. The equivalent circuit , under b. shown, consists of two bipolar transistors with one npn and one pnp transistor each. The circuit symbol is under c. pictured. The two connections of the four-layer diode are called anode and cathode .

If a certain voltage of the corresponding polarity is exceeded at the connections, ignition occurs: The four-layer diode becomes low-resistance. This state remains until a certain holding current is undershot. The component then switches back to its initial high-resistance state. This function corresponds to the so-called overhead ignition (English breakover ) of a thyristor. Thyristors, which are specially designed for overhead ignition, are also referred to as dynistors and are used in power electronics . The behavior of the four-layer diode is similar to the multilayer diodes ( diacs ) designed for alternating voltage .

Four-layer diodes were used as low-power switch components, mainly to control thyristors.

Characteristic curve and typical values

curve
description Area Typical
Forward operation
Switching voltage U S 10V to 250V 50V ± 4V
Holding voltage U H 0.5V to 2V 0.8V
Switching current I S a few µA to a few mA 120 µA
Holding current I H 1 to 50 mA 14 to 45 mA
Reverse operation
Reverse current I R 15µA
Max. Permissible reverse voltage U RMax

(Zener voltage U Z )

10 V to 250 V. 60 V

Alternative names and symbols

In the literature, other names and symbols are also used for the four-layer diode, some of which are also used for diacs:

  • Thyristor diode
  • Trigger diode
  • Breakover diode
  • 4-layer transistor diode
  • pnpn diode

In the symbol that was also used by Shockley, one recognizes the number four:

Web links

Commons : Shockley diodes  - collection of images, videos and audio files
Wikibooks: Four-layer diode  - learning and teaching materials

Individual evidence

  1. a b c d Klaus Beuth: Components (=  electronics . Volume 2 ). 17th edition. Vogel technical book, Waldkirch 2003, ISBN 3-8023-1957-5 .
  2. a b Hans-Joachim Fischer: electronica amateur series: Introduction to diode and transistor technology, Part 1: Diode technology . German Military Publishing House, Berlin 1970, p. 117 .
  3. a b Photo Essay - Shockley 4 Layer Diodes . Transistor Museum, last accessed on April 16, 2013.
  4. Shockley Diode & DIAC , last accessed on April 16, 2013
  5. a b Willfried Schurig: electronica amateur series: characteristics of electronic components. Part II: Semiconductor Diodes . German Military Publishing House, Berlin 1971, p. 119 .
  6. Electrical engineering - electronics - basics and terms. VEB Fachbuchverlag, 1984.