Four layer diode
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Today it has been replaced by other semiconductor components , in particular the diac , and is no longer of economic importance.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
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
- Photo Essay - Shockley 4 Layer Diodes . Transistor Museum (English); Retrieved December 15, 2010
- The Shockley Diode (English); Retrieved December 15, 2010
Individual evidence
- ↑ a b c d Klaus Beuth: Components (= electronics . Volume 2 ). 17th edition. Vogel technical book, Waldkirch 2003, ISBN 3-8023-1957-5 .
- ↑ 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 .
- ↑ a b Photo Essay - Shockley 4 Layer Diodes . Transistor Museum, last accessed on April 16, 2013.
- ↑ Shockley Diode & DIAC , last accessed on April 16, 2013
- ↑ a b Willfried Schurig: electronica amateur series: characteristics of electronic components. Part II: Semiconductor Diodes . German Military Publishing House, Berlin 1971, p. 119 .
- ↑ Electrical engineering - electronics - basics and terms. VEB Fachbuchverlag, 1984.