Power Semiconductor Devices: Abbreviations, Symbols

Abbreviations of Power Semiconductor Devices

The first step to power electronics course is understanding the Power Semiconductor Devices. They are fundamental blocks to study the Power Electronics.

Why symbols are required?

The schematic is the first step in designing an electronic controller. After a rough sketch, the diagram is put into tentative form known as schematic diagram. For analysis of a circuit function, or malfunction, the schematic drawing is the fundamental one. In the schematic diagram, various electrical and electronics components are represented by their unique symbols.

In this post, we have given the abbreviations and symbols of various Power Semiconductor Devices. Various Posts were published to explain the structure, operation and applications of these devices. Frequently we will forget these abbreviations, symbols at initial stage. This post will serve as a quick reference for you.

Commercially available power semiconductor devices could be categorized in to several basic groups such as diodes, thyristors, bipolar junction power transistors, Power metal oxide silicon field effect transistors, Insulated gate bipolar transistors, MOS controlled thyristors and gate turn off thyristors(GTO) etc.

 BJT - Bipolar Junction Transistor
UJT - Uni Junction Transistor
SCR - Silicon Controlled Rectifier
GTO - Gate Turnoff Thyristor
RCT - Reverse Conducting Thyristor
MCT - MOS Controlled Thyristor
TRIAC - TRIode for Alternating Current
DIAC - DIode on AC
MOSFET - Metal Oxide Semiconductor Field Effect Transistor
IGBT - Insulated Gate Bipolar Transistor
SIT - Static Induction Transistor
SITH - Static Induction Thyristor
IGCT - Integrated Gate Commutated Thyristor ( also known as GCT)
LTT (LASCR) - Light Triggered(Activated) Thyristor

Symbols of Power Semiconductor Devices:

Power Diode
It is a two terminal P-N junction device.  The terminals are namely Anode and Cathode.

UJT: Uni Junction Transistor
It has three terminals namely Emitter (E), base1(B1) and base2(B2)

Power BJT

SCR: Silicon Controlled Rectifier

It has three terminals namely Anode (A), cathode(K) and Gate(G).
When the Anode terminal is positive with respect to cathode (K) terminal device is in forward blocking mode.
Now if the voltage is applied to the gate terminal with respect to the cathode, the device will start to conduct.
As the name indicates it is made up of silicon.
It works as a rectifier. Its operation as a rectifier is controllable.

GTO:  Gate Turnoff Thyristor
It has three terminals namely Anode(A), Cathode(K) and Gate (G).

MCT (n-channel): MOS Controlled Thyristor
It is has three terminals namely Anode, Cathode and Gate

MOSFET: Metal Oxide Semiconductor Field Effect Transistor

IGBT: Insulated Gate Bipolar junction Transistor ( both the symbols are applicable)

RCT: Reverse Conducting Thyristor
This power semiconductor device is similar to SCR in addition to that it can be conduct current from cathode to anode too.

LTT or LASCR: Light Triggered(Activated) Thyristor
It is similar to SCR except that instead of applying voltage to the gate terminal, by applying light to the notch provided in the device, we can trigger it.

TRIAC: TRIode for Alternating Current
It is a five layer device. It has three terminals namely Terminal-1, Terminal-2 and gate.

DIAC: DIode on AC

Read More:
Power Electronics System: Introduction,Advantages, Disadvantages
Applications of Power Electronics in Various Fields
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4 Responses

  1. Sandi says:

    Thank's for the article. It's useful.

  2. pavani chowdary says:

    thank you..

  3. Thankyou for this information...

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