Semiconductor Schematic Symbols

In this article we will see semiconductor schematic symbols. Semiconductor symbols are used to represent various electronic devices and components as pictograms. A typical electrical or electronic symbol consists of a main line, along with one or more identification symbols. Letter symbols, numbers, and subscripts based on roman and Greek alphabets are commonly used in contingent with a semiconductor symbol to identify different input or output terminals according to the traditional current flow.

The shape and outlines of a semiconductor symbol are used to represent their exact work and current flow direction for connection to the correct electrical polarities that allow them to be connected together. The physical placement and positioning of semiconductor devices on the circuit board is usually quite different from the circuit diagram.

The graphic symbols used in electrical circuit diagrams are wide and varied, and most of these symbols differ from country to country. These days, semiconductor symbols are internationally standardized with symbols for diodes, transistors and power electronics devices with a common design. The symbols listed below follow the recommendations of the International Electrotechnical Commission (IEC) and the British Standards Institute (BSI).

Schematic Symbols for Semiconductor Diodes

There are many different types of semiconductor devices that can be classified as diodes, and for most of these types there is a separate circuit symbol. Some of the main types of diode are pn-connection, Schottky, photo diode and light-emitting diode. For each of these types of diode, schematic symbols use the same basic diode format, but are modified to show their different functions.

Diodes are two-terminal devices consisting of two semiconductor materials fused together to form a pn-connection in which the "n" type material is the cathode and the "p" type material is the anode. Usually a diode cathode tip is defined by a colored tape.

The basic schematic symbol of a diode looks like an arrowhead, indicating the flow of traditional current from terminal Anode (A) to The Cathode (K) terminal. The schematic symbol of a diode also indicates that the current will flow in the direction of the arrow, if it is forward-oriented. However, if the polarity of the voltage is inverse, the current does not flow.

The schematic symbol for zener diode and Schottky diode resembles the basic pn-link diode, except that the line representing the symbol's Cathode (K) terminal bends at both ends. The schematic symbol of a light-emitting diode (LED) indicates the light energy shown by the smaller arrows emitted from it when it is forward-facing.

Semiconductor Schematic Symbols
Schematic Symbols for Semiconductor Diodes

Schematic Symbols for Bipolar Junction Transistors

Schematic symbols used for bipolar connection transistors or BJTs indicate two main types, NPN (Negative-Positive-Negative) transistors, and PNP (Positive-Negative-Positive) transistors. Bipolar transistor symbols with circles around them indicate a separate device, while those that do not contain circles indicate their use in an internal circuit. For example, logic gates and digital IC's.

Bipolar transistors are 3-terminal devices with the schematic symbol of a bipolar transistor marked with the letters "C", "B" and "E", which correspond to collector, base and emitter terminals respectively. Conventional current flows from the transmitter terminal to the collector terminal via a bipolar transistor, while the Base terminal controls the amount of current flow. Normally, these identification letters are not used in circuit diagrams, but are included here to make them understandable.

Other types of bipolar transistor circuit symbols include those for Darlington transistors, where two bipolar transistors are connected to form a single device, and phototransistors that use light energy instead of a Base terminal to work.

Semiconductor Schematic Symbols
Schematic Symbols for Bipolar Junction Transistors

Schematic Symbols for Field-Effective Transistors

Field Effective Transistors, or FET's, are 3-terminal devices that come in a wide variety of different types, each with its own semiconductor symbol to describe its operation. Schematic symbols used to represent field-effective transistors are marked with the letters "D", "G" and "S", respectively, corresponding to the Drain, Gate, and Source terminals.

The two main types of field-effective transistors are: Junction FETs or JFETs and Isolated Door FET's or IGFETs. Junction FET's have a symbol that uses an arrow to indicate the direction of traditional current flow from diode connections. Insulated Door FET's, commonly called MOSFET due to metal, oxide and silicone structure forms, have a schematic symbol indicating the Door insulated from the Drain-to-Source channel. Both JFET and IGFET (MOSFET) are available as N-channel or P-channel types.

Semiconductor Schematic Symbols
Schematic Symbols for Field-Effective Transistors

Schematic Symbols for Power Electronics Devices

Power semiconductor devices are a series of electronic devices used to convert, control or replace electrical power in electrical circuits. The electrical power controlled by these semiconductor devices is much greater than those usually controlled by bipolar transistors or the above area-effective transistors.

Power electronic semiconductor devices such as thyristors and Triages are voltage-powered components used to modify and control AC sources for use in controlled rectifiers, power supplies or AC engine driver controllers. Power electronics devices, together with the components detailed above, are finding new applications in energy, power, industrial and transportation applications such as renewable energy technologies, battery charging systems, energy storage, solar energy inverters, electric vehicles, power converters, HVAC and more. .

Power electronics circuits and applications differ from digital or small circuit electronic systems in terms of efficiency, size and power processing capabilities with the following components, which are silicon-controlled rectifiers, door closure rectifiers, triage and diaklar key components.

Semiconductor Schematic Symbols
Schematic Symbols for Power Electronics Devices