Symbols on electrical wiring diagrams. Conventional graphic symbols in electrical circuits. Types and types of electrical circuits

Electrical diagram- this is a text that describes with certain symbols the content and operation of an electrical device or a set of devices, which allows this text to be expressed in a concise form.

In order to read any text, you need to know the alphabet and reading rules. So, to read diagrams, you should know the symbols - conventions and rules for deciphering their combinations.

The basis of any electrical circuit is graphic symbols various elements and devices, as well as connections between them. The language of modern circuits emphasizes in symbols the main functions that the depicted element performs in the circuit. All correct conventional graphic designations of electrical circuit elements and their individual parts are given in the form of tables in the standards.

Conventional graphic symbols are formed from simple geometric shapes: squares, rectangles, circles, as well as from solid and dashed lines and dots. Their combination according to a special system, which is provided by the standard, makes it possible to easily depict everything that is required: various electrical devices, instruments, electrical machines, mechanical and electrical connection lines, types of winding connections, type of current, nature and methods of regulation, etc.

In addition, in the conventional graphic symbols on electrical circuit diagrams, special symbols are additionally used to explain the operating features of a particular circuit element.

For example, there are three types of contacts - normally open, normally closed and switching. The symbols reflect only the main function of the contact - closing and opening the circuit. To indicate additional functionality of a specific contact, the standard provides for the use of special characters applied to the image of the moving part of the contact. Additional signs allow you to find contacts, time relays, limit switches, etc. on the diagram.

Individual elements on electrical diagrams have not one, but several options for designation on the diagrams. For example, there are several equivalent options for designating switching contacts, as well as several standard designations for transformer windings. Each of the designations can be used in certain cases.

If the standard does not contain the required designation, then it is compiled based on the principle of operation of the element, designations adopted for similar types of devices, devices, machines in compliance with the design principles stipulated by the standard.

Standards. Conventional graphic symbols on electrical and automation diagrams:

GOST 2.710-81 Alphanumeric designations in electrical circuits:

The ability to read electrical diagrams is an important component, without which it is impossible to become a specialist in the field of electrical installation work. Every novice electrician must know how sockets, switches, switching devices and even an electricity meter are designated on a wiring project in accordance with GOST. Next, we will provide readers of the site with symbols in electrical circuits, both graphic and alphabetic.

Graphic

As for the graphic designation of all elements used in the diagram, we will provide this overview in the form of tables in which the products will be grouped by purpose.

In the first table you can see how electrical boxes, panels, cabinets and consoles are marked on electrical circuits:

The next thing you should know is the symbol for power sockets and switches (including walk-through ones) on single-line diagrams of apartments and private houses:

As for lighting elements, lamps and lamps according to GOST are indicated as follows:

In more complex circuits where electric motors are used, elements such as:

It is also useful to know how transformers and chokes are graphically indicated on circuit diagrams:

Electrical measuring instruments according to GOST have the following graphic designation on the drawings:

By the way, here is a table useful for novice electricians, which shows what the ground loop looks like on a wiring plan, as well as the power line itself:

In addition, in the diagrams you can see a wavy or straight line, “+” and “-”, which indicate the type of current, voltage and pulse shape:

In more complex automation schemes, you may encounter incomprehensible graphic symbols, such as contact connections. Remember how these devices are designated on electrical diagrams:

In addition, you should be aware of what radio elements look like on projects (diodes, resistors, transistors, etc.):

That's all the conventional graphic symbols in the electrical circuits of power circuits and lighting. As you have already seen for yourself, there are quite a lot of components and remembering how each is designated can only be done with experience. Therefore, we recommend that you save all these tables so that when reading the wiring plan for a house or apartment, you can immediately determine what kind of circuit element is located in a certain place.

Interesting video

Any electrical circuits can be presented in the form of drawings (circuit and wiring diagrams), the design of which must comply with ESKD standards. These standards apply to both electrical wiring or power circuits and electronic devices. Accordingly, in order to “read” such documents, it is necessary to understand the symbols in electrical circuits.

Regulatory documents

Taking into account the large number of electrical elements, a number of normative documents have been developed for their alphanumeric (hereinafter referred to as BO) and conventional graphic designations (UGO) to eliminate discrepancies. Below is a table showing the main standards.

Table 1. Standards for graphic designation of individual elements in installation and circuit diagrams.

It should be taken into account that the element base changes over time, and accordingly changes are made to regulatory documents, although this process is more inert. Let's give a simple example: RCDs and automatic circuit breakers have been widely used in Russia for more than a decade, but there is still no single standard according to GOST 2.755-87 for these devices, unlike circuit breakers. It is quite possible that this issue will be resolved in the near future. To keep abreast of such innovations, professionals monitor changes in regulatory documents; amateurs do not have to do this; it is enough to know the decoding of the main symbols.

Types of electrical circuits

In accordance with ESKD standards, diagrams mean graphic documents on which, using accepted notations, the main elements or components of a structure, as well as the connections connecting them, are displayed. According to the accepted classification, ten are distinguished, of which three are most often used in electrical engineering:

If the diagram shows only the power part of the installation, then it is called single-line; if all elements are shown, then it is called complete.

If the drawing shows the wiring of the apartment, then the locations of lighting fixtures, sockets and other equipment are indicated on the plan. Sometimes you can hear such a document called a power supply diagram; this is incorrect, since the latter shows how consumers are connected to a substation or other power source.

Having dealt with the electrical circuits, we can move on to the designations of the elements indicated on them.

Graphic symbols

Each type of graphic document has its own designations, regulated by relevant regulatory documents. Let us give as an example the basic graphic symbols for different types of electrical circuits.

Examples of UGO in functional diagrams

Below is a picture depicting the main components of automation systems.

Description of symbols:

• A – Basic (1) and acceptable (2) images of devices that are installed outside the electrical panel or junction box.
• B - The same as point A, except that the elements are located on the remote control or electrical panel.
• C – Display of actuators (AM).
• D – Influence of MI on the regulating body (hereinafter referred to as RO) when the power is turned off:

1. RO opening occurs
2. Closing RO
3. The position of the RO remains unchanged.

• E - IM, on which a manual drive is additionally installed. This symbol may be used for any RO provisions specified in paragraph D.
• F- Accepted mappings of communication lines:

1. General.
2. There is no connection at the intersection.
3. The presence of a connection at the intersection.

UGO in single-line and complete electrical circuits

There are several groups of symbols for these schemes; we present the most common of them. To obtain complete information, you must refer to the regulatory documents; the numbers of state standards will be given for each group.

Power supplies.

To designate them, the symbols shown in the figure below are used.

Description of symbols:

• A is a constant voltage source, its polarity is indicated by the symbols “+” and “-”.
• B – electricity icon indicating alternating voltage.
• C is a symbol of alternating and direct voltage, used in cases where the device can be powered from any of these sources.
• D – Display of battery or galvanic power source.
• E- Symbol of a battery consisting of several batteries.

Communication lines

The basic elements of electrical connectors are presented below.

Description of symbols:

• A – General display adopted for various types of electrical connections.
• B – Current-carrying or grounding bus.
• C – Designation of shielding, can be electrostatic (marked with the symbol “E”) or electromagnetic (“M”).
• D - Grounding symbol.
• E – Electrical connection with the device body.
• F - On complex diagrams, consisting of several components, a broken connection is thus indicated; in such cases, “X” is information about where the line will be continued (as a rule, the element number is indicated).
• G – Intersection with no connection.
• H – Joint at intersection.
• I – Branches.

Designations of electromechanical devices and contact connections

Examples of the designation of magnetic starters, relays, as well as contacts of communication devices can be seen below.

Description of symbols:

• A – symbol of the coil of an electromechanical device (relay, magnetic starter, etc.).
• B – UGO of the receiving part of the electrothermal protection.
• C – display of the coil of a device with a mechanical lock.
• D – contacts of switching devices:

1. Closing.
2. Disconnecting.
3. Switching.

• E – Symbol for designating manual switches (buttons).
• F – Group switch (switch).

UGO of electric machines

Let us give several examples of displaying electrical machines (hereinafter referred to as EM) in accordance with the current standard.

Description of symbols:

• A – three-phase EM:

1. Asynchronous (squirrel-cage rotor).
2. Same as point 1, only in two-speed version.
3. Asynchronous electric motors with phase-phase rotor design.
4. Synchronous motors and generators.

• B – Collector, DC powered:

1. EM with permanent magnet excitation.
2. EM with excitation coil.

UGO transformers and chokes

Examples of graphic symbols for these devices can be found in the figure below.

Description of symbols:

• A – This graphic symbol can indicate inductors or windings of transformers.
• B – Choke, which has a ferrimagnetic core (magnetic core).
• C – Display of a two-coil transformer.
• D – Device with three coils.
• E – Autotransformer symbol.
• F – Graphic display of CT (current transformer).

Designation of measuring instruments and radio components

A brief overview of these electronic components is shown below. For those who want to become more familiar with this information, we recommend viewing GOSTs 2.729 68 and 2.730 73.

Description of symbols:

1. Electricity meter.
2. Picture of an ammeter.
3. Device for measuring network voltage.
4. Thermal sensor.
5. Fixed value resistor.
6. Variable resistor.
7. Capacitor (general designation).
8. Electrolytic capacity.
9. Diode designation.
10. LED
11. Image of a diode optocoupler.
12. UGO transistor (in this case npn).
13. Fuse designation.

UGO lighting devices

Let's look at how electric lamps are displayed on a circuit diagram.

Description of symbols:

• A – General image of incandescent lamps (LN).
• B - LN as a signaling device.
• C – Typical designation of gas-discharge lamps.
• D – High-pressure gas-discharge light source (the figure shows an example of a design with two electrodes)

Designation of elements in the wiring diagram

Concluding the topic of graphic symbols, we give examples of displaying sockets and switches.

How sockets of other types are depicted is easy to find in the regulatory documents that are available on the Internet.

When carrying out electrical work, each person, one way or another, encounters the symbols that are in any electrical circuit. These diagrams are very diverse, with different functions, however, all graphic symbols are given the same form and correspond to the same elements in all diagrams.

The main symbols in GOST electrical circuits are shown in tables

Currently, not only domestic elements are used in electrical engineering and radio electronics, but also products manufactured by foreign companies. Imported electrical and radio elements make up a huge range. They are necessarily displayed in all drawings in the form of symbols. They determine not only the values ​​of the main electrical parameters, but also a complete list of them included in a particular device, as well as the relationship between them.

To read and understand the contents of an electrical diagram

You need to thoroughly study all the elements that make up it and the principle of operation of the device as a whole. Typically, all information is found either in reference books or in the specification attached to the circuit. Positional designations characterize the relationship of the elements included in the device kit with their designations on the diagram. In order to graphically designate one or another electrical radio element, standard geometric symbolism is used, where each product is depicted separately or in combination with others. The meaning of each individual image largely depends on the combination of symbols with each other.

Each diagram shows

Connections between individual elements and conductors. In such cases, the standard designation of identical components and elements is of no small importance. This is why there are positional designations, where the types of elements, their design features and digital values ​​are displayed in letter expression. Elements used in the general order are designated in the drawings as qualification ones, characterizing current and voltage, control methods, types of connections, pulse shapes, electronic communications and others.

In this article we will look at the designation of radio elements on diagrams.

Where to start reading diagrams?

In order to learn how to read circuits, first of all, we must study what a particular radio element looks like in a circuit. In principle, there is nothing complicated about this. The whole point is that if the Russian alphabet has 33 letters, then in order to learn the symbols of radio elements, you will have to try hard.

Until now, the whole world cannot agree on how to designate this or that radio element or device. Therefore, keep this in mind when you collect bourgeois schemes. In our article we will consider our Russian GOST version of the designation of radioelements

Studying a simple circuit

Okay, let's get to the point. Let's look at a simple electrical circuit of a power supply, which used to appear in any Soviet paper publication:

If this is not the first day you have held a soldering iron in your hands, then everything will immediately become clear to you at first glance. But among my readers there are also those who encounter such drawings for the first time. Therefore, this article is mainly for them.

Well, let's analyze it.

Basically, all diagrams are read from left to right, just like you read a book. Any different circuit can be represented as a separate block to which we supply something and from which we remove something. Here we have a circuit of a power supply to which we supply 220 Volts from the outlet of your house, and a constant voltage comes out of our unit. That is, you must understand what is the main function of your circuit?. You can read this in the description for it.

How are radioelements connected in a circuit?

So, it seems that we have decided on the task of this scheme. Straight lines are wires or printed conductors through which electric current will flow. Their task is to connect radioelements.

The point where three or more conductors connect is called knot. We can say that this is where the wiring is soldered:

If you look closely at the diagram, you can see the intersection of two conductors

Such intersection will often appear in diagrams. Remember once and for all: at this point the wires are not connected and they must be insulated from each other. In modern circuits, you can most often see this option, which already visually shows that there is no connection between them:

Here, it is as if one wire goes around the other from above, and they do not contact each other in any way.

If there was a connection between them, then we would see this picture:

Letter designation of radioelements in the circuit

Let's look at our diagram again.

As you can see, the diagram consists of some strange icons. Let's look at one of them. Let this be the R2 icon.

So, let's first deal with the inscriptions. R means . Since we have him not the only one in the scheme, the developer of this scheme gave him the serial number “2”. There are as many as 7 of them in the diagram. Radio elements are generally numbered from left to right and top to bottom. A rectangle with a line inside already clearly shows that this is a constant resistor with a dissipation power of 0.25 Watt. It also says 10K next to it, which means its denomination is 10 Kilohms. Well, something like this...

How are the remaining radioelements designated?

Single-letter and multi-letter codes are used to designate radioelements. Single letter codes are group, to which this or that element belongs. Here are the main ones groups of radioelements:

A – these are various devices (for example, amplifiers)

IN – converters of non-electrical quantities into electrical ones and vice versa. This may include various microphones, piezoelectric elements, speakers, etc. Generators and power supplies here do not apply.

WITH – capacitors

D – integrated circuits and various modules

E – miscellaneous elements that do not fall into any group

F – arresters, fuses, protective devices

H – indicating and signaling devices, for example, sound and light indicating devices

K – relays and starters

L – inductors and chokes

M – engines

R – instruments and measuring equipment

Q – switches and disconnectors in power circuits. That is, in circuits where high voltage and high current “walk”

R – resistors

S – switching devices in control, signaling and measurement circuits

T – transformers and autotransformers

U – converters of electrical quantities into electrical ones, communication devices

V – semiconductor devices

W – microwave lines and elements, antennas

X – contact connections

Y – mechanical devices with electromagnetic drive

Z – terminal devices, filters, limiters

To clarify the element, after the one-letter code there is a second letter, which already indicates element type. Below are the main types of elements along with the letter group:

BD – ionizing radiation detector

BE – selsyn receiver

B.L. – photocell

BQ – piezoelectric element

BR – speed sensor

B.S. – pickup

B.V. – speed sensor

B.A. – loudspeaker

BB – magnetostrictive element

B.K. – thermal sensor

B.M. – microphone

B.P. – pressure sensor

B.C. – selsyn sensor

D.A. – integrated analog circuit

DD – integrated digital circuit, logical element

D.S. – information storage device

D.T. – delay device

EL - lighting lamp

E.K. – heating element

F.A. – instantaneous current protection element

FP – inertial current protection element

F.U. – fuse

F.V. – voltage protection element

G.B. - battery

HG – symbol indicator

H.L. – light signaling device

H.A. – sound alarm device

KV – voltage relay

K.A. – current relay

KK – electrothermal relay

K.M. – magnetic starter

KT – time relay

PC – pulse counter

PF – frequency meter

P.I. – active energy meter

PR – ohmmeter

PS – recording device

PV – voltmeter

PW – wattmeter

PA – ammeter

PK – reactive energy meter

P.T. - watch

QF

QS – disconnector

RK – thermistor

R.P. – potentiometer

R.S. – measuring shunt

RU – varistor

S.A. – switch or switch

S.B. – push-button switch

SF – automatic switch

S.K. – temperature-triggered switches

SL – switches activated by level

SP – pressure switches

S.Q. – switches activated by position

S.R. – speed-triggered switches

TV – voltage transformer

T.A. – current transformer

UB – modulator

UI – discriminator

UR – demodulator

UZ – frequency converter, inverter, frequency generator, rectifier

VD – diode, zener diode

VL – electrovacuum device

VS – thyristor

VT –

W.A. – antenna

W.T. – phase shifter

W.U. – attenuator

XA – current collector, sliding contact

XP – pin

XS - nest

XT – collapsible connection

XW – high frequency connector

YA – electromagnet

YB – brake with electromagnetic drive

YC – clutch with electromagnetic drive

YH – electromagnetic plate

ZQ – quartz filter

Graphic designation of radioelements in the circuit

I will try to give the most common designations of elements used in the diagrams:

Resistors and their types

A) general designation

b) dissipation power 0.125 W

V) dissipation power 0.25 W

G) dissipation power 0.5 W

d) dissipation power 1 W

e) dissipation power 2 W

and) dissipation power 5 W

h) dissipation power 10 W

And) dissipation power 50 W

Variable resistors

Thermistors

Strain gauges

Varistors

Shunt

Capacitors

a) general designation of a capacitor

b) variconde

V) polar capacitor

G) trimmer capacitor

d) variable capacitor

Acoustics

a) headphone

b) loudspeaker (speaker)

V) general designation of a microphone

G) electret microphone

Diodes

A) diode bridge

b) general designation of a diode

V) zener diode

G) double-sided zener diode

d) bidirectional diode

e) Schottky diode

and) tunnel diode

h) reversed diode

And) varicap

To) LED

l) photodiode

m) emitting diode in the optocoupler

n) radiation receiving diode in the optocoupler

Electrical quantity meters

A) ammeter

b) voltmeter

V) voltammeter

G) ohmmeter

d) frequency meter

e) wattmeter

and) faradometer

h) oscilloscope

Inductors

A) coreless inductor

b) inductor with core

V) tuning inductor

Transformers

A) general designation of a transformer

b) transformer with winding output

V) current transformer

G) transformer with two secondary windings (maybe more)

d) three-phase transformer

Switching devices

A) closing

b) opening

V) opening with return (button)

G) closing with return (button)

d) switching

e) reed switch

Electromagnetic relay with different groups of contacts

Fuses

A) general designation

b) the side that remains energized when the fuse blows is highlighted

V) inertial

G) fast acting

d) thermal coil

e) switch-disconnector with fuse

Thyristors

Bipolar transistor

Unijunction transistor