To read electrical diagrams, you need to know and remember well: the most common symbols of windings, contacts, transformers, motors, rectifiers, lamps, etc., symbols used in the area that you mainly encounter due to your profession, diagram the most common components of electrical installations, for example motors, rectifiers, lighting with incandescent and gas-discharge lamps, etc., properties of series and parallel connections of contacts, windings, resistances, inductances and capacitances.
Dividing circuits into simple circuits
Any electrical installation meets certain operating conditions.
Therefore, when reading the diagrams, firstly, it is necessary to identify these conditions, secondly, to determine whether the obtained conditions correspond to the tasks that must be solved by the electrical installation, and thirdly, it is necessary to check whether “extra” conditions have arisen along the way, and evaluate them consequences.
To solve these issues, several techniques are used.
The first of them is that the electrical installation diagram is mentally divided into simple circuits, which are first considered separately and then in combination. A simple circuit includes a current source (battery, transformer secondary, charged capacitor, etc.), a current receiver (motor, resistor, lamp, relay winding, discharged capacitor, etc.), a direct wire (from the current source to the receiver ), return wire (from the current receiver to the source) and one contact of the device (switch, relay, etc.). It is clear that in circuits that do not allow opening, for example in circuits of current transformers, there are no contacts.
When reading a diagram, you must first mentally break it down into simple circuits to check the capabilities of each element, and then consider their joint action.
The reality of circuit solutions Engineers know well that circuit solutions cannot always be implemented in practice, although they do not contain obvious errors.. Therefore, one of the tasks of reading electrical diagrams is to check whether given conditions can be met.
The unreality of circuit solutions usually has mainly the following reasons:
there is not enough energy to operate the device,
“excess” energy penetrates into the circuit, causing unexpected operation or preventing the timely release of the electrical device,
there is not enough time to complete the specified actions,
the device has set a setpoint that cannot be achieved,
devices that differ sharply in properties are used together,
switching capacity, insulation level of devices and wiring are not taken into account, switching overvoltages are not suppressed,
the conditions in which the electrical installation will be operated are not taken into account,
When designing an electrical installation, its operating state is taken as a basis, but the question of how to bring it into this state and in what state it will end up, for example, as a result of a short-term power interruption, is not resolved.
How to Read Electrical Diagrams and Drawings
First of all, you need to familiarize yourself with the available drawings (or create a table of contents if there is none) and systematize the drawings (if this is not done in the project) according to their intended purpose.
The drawings are alternated in such an order that reading each subsequent one is a natural continuation of reading the previous one. Then understand the accepted system of notation and labeling.
If it is not reflected in the drawings, then it is found out and written down.
On the selected drawing, read all the inscriptions, starting with the stamp, then notes, explications, explanations, specifications, etc. When reading the explication, be sure to find the devices listed in it on the drawings. When reading the specifications, compare them with the explanations.
If the drawing contains links to other drawings, then you need to find these drawings and understand the contents of the links.
For example, one circuit includes a contact that belongs to a device shown in another circuit. This means that you need to understand what kind of device it is, what it is used for, under what conditions it works, etc.
When reading drawings covering power supply, electrical protection, control, alarm, etc.:
2) break down the scheme into simple prices and, considering their combination, establish the conditions of action. We always begin to consider the device that interests us in this case. For example, if the engine does not work, then you need to find its circuit on the diagram and see which devices contacts are included in it.
Then they find the circuits of the devices that control these contacts, etc.,
3) build interaction diagrams, using them to clarify: the sequence of work in time, the consistency of the operation time of devices within a given device, the consistency of the operation time of jointly operating devices (for example, automation, protection, telemechanics, controlled drives, etc.), consequences power interruption. To do this, one by one, assuming that the switches and power supply circuit breakers are turned off (the fuses are blown), they evaluate the possible consequences, the possibility of the device returning to the operating position from any state in which it could find itself, for example, after an inspection,
4) assess the consequences of probable faults: non-closure of contacts one at a time, violations of insulation relative to the ground one by one for each section,
5) violation of insulation between the wires of overhead lines extending outside the premises, etc.,
5) check the circuit for the absence of false circuits,
6) evaluate the reliability of the power supply and the operating mode of the equipment,
7) check the implementation of measures to ensure safety, subject to the organization of work stipulated by the current rules (PUE, SNiP, etc.).
Knowing the general appearance of radio components, you can, of course, to some extent understand the structure of the radio-electronic device, but still the radio amateur will have to draw on paper the contours of the parts and the connection between them.
Back in the last century, in order to preserve the design and circuit solutions of radio devices, the pioneers of radio engineering made drawings of them. If you look at these drawings, you can see that they were made at a very high artistic level.
This was usually done by the inventors themselves, if they had the ability, or by invited artists. Drawings of structures and connections of parts were made from life.
A lot of time and sometimes money could be spent on drawing an approximate view of a part; in those days it was not yet possible to use computers and programs for drawing diagrams.
The details were drawn in detail. For example, in 1905, an inductor coil was depicted in isometry, that is, in three-dimensional space, with all the details, frame, winding, number of turns (Fig. 1). In the end, images of parts and their connections began to be made conditionally, symbolically, but at the same time preserving their features.
Rice. 1. Evolution of the conventional graphic image of an inductor on electrical circuits
In 1915, the drawing of the circuits was simplified; the frame was no longer depicted; instead, lines of different thicknesses were used to emphasize the cylindrical shape of the coil.
After 40 years, the coil was already depicted with lines of the same thickness, but still preserving the original features of its appearance. Only in the early 70s of our century did the coil begin to be depicted as flat, that is, two-dimensional, and radio-electronic circuits began to take on their current form. Drawing complex electronic circuits is very labor-intensive work. To carry it out, an experienced draftsman-designer is required.
In order to simplify the process of drawing diagrams, the American inventor Cecil Effinger designed a typewriter in the late 60s of the 20th century.
In the machine, instead of the usual letters, symbols for resistors, capacitors, diodes, etc. were inserted. The work of making radio circuits on such a machine became accessible to even a simple typist. With the advent of personal computers, the process of making radio circuits has been greatly simplified.
Now, knowing a graphic editor, you can draw an electronic circuit on a computer screen and then print it on a printer. Due to the expansion of international contacts, the symbols of radio circuits have been improved and now they are not very different from each other in different countries. This makes radio circuits understandable to radio technicians around the world.
The third technical committee of the International Electrotechnical Commission (IEC) deals with the graphic symbols and rules for the execution of electrical circuits.
In radio electronics, three types of circuits are used: block diagrams, circuit diagrams and wiring diagrams. In addition, to check electronic equipment, voltage and resistance maps are drawn up.
Block diagrams do not reveal the specifics of the details, the number of ranges, the number of transistors, or the circuit by which certain nodes are assembled; it only gives a general idea of the composition of the equipment and the interconnection of its individual nodes and blocks. The schematic diagram shows the symbols of the elements of the device or blocks and their electrical connections.
Schematic diagram does not give any idea about the appearance, or the arrangement of parts on the board, or how to arrange the connecting wires. This can only be found out from the wiring diagram.
It should be noted that on the wiring diagram the parts are depicted in such a way that their appearance resembles their real outlines. To check the operating modes of electronic equipment, special voltage and resistance maps are used. These maps indicate voltage and resistance values relative to the chassis or ground wire.
In our country, when drawing radio-electronic circuits, we are guided by the state standard, abbreviated as GOST, which indicates how certain radio components should be conventionally depicted.
To make it easier to remember the symbols of individual elements of electronic equipment, their images contain characteristic features of the parts. On the diagrams, an alphanumeric designation is placed next to the conventional graphic image.
The designation consists of one or two letters of the Latin alphabet and numbers indicating the serial number of this part in the diagram. Serial numbers of graphic images of radio components are placed based on the sequence of arrangement of similar symbols, for example, in the direction from left to right or from top to bottom.
Latin letters indicate the type of part, C - capacitor, R - resistor, VD - diode, L - inductor, VT - transistor, etc. Next to the alphanumeric designation of the part, the value of its main parameter (capacitance of the capacitor, resistor resistance, inductance, etc.) and some additional information are indicated. The most commonly used conventional graphic images of radio components on circuit diagrams are given in Table. 1, and their letter designations (codes) are given in table. 2.
At the end of the positional designation a letter may be placed indicating its functional purpose, table. 3. For example, R1F is a protective resistor, SB1R is a reset button.
To increase the information richness of a printed publication, in the scientific and technical literature on radio electronics, as well as in various diagrams related to this field of knowledge, conventional letter abbreviations for devices and the physical processes occurring in them are used. In table 4 shows the most commonly used abbreviations and their interpretation.
Table 1. Symbols of radio components on circuit diagrams.
Table 2. Letter designations (codes) of radio components on circuit diagrams.
| Devices and elements | Letter code |
| Devices: amplifiers, remote control devices, lasers, masers; general designation | A |
| Converters of non-electrical quantities into electrical ones (except for generators and power supplies) or vice versa, analogue or multi-digit converters, sensors for indicating or measuring; general designation | IN |
| Speaker | VA |
| Magnetostrictive element | BB |
| Ionizing radiation detector | BD |
| Selsyn sensor | Sun |
| Selsyn receiver | BE |
| Telephone (capsule) | B.F. |
| Thermal sensor | VC |
| Photocell | B.L. |
| Microphone | VM |
| Pressure meter | VR |
| Piezo element | IN |
| Speed sensor, tachogenerator | BR |
| Pickup | B.S. |
| Speed sensor | VV |
| Capacitors | WITH |
| Integrated circuits, microassemblies: general designation | D |
| Integrated analog microcircuit | D.A. |
| Integrated digital microcircuit, logical element | DD |
| Information storage device (memory) | D.S. |
| Delay device | D.T. |
| Various elements: general designation | E |
| Lighting lamp | EL |
| A heating element | EC |
| Arresters, fuses, protection devices: general designation | F |
| fuse | F.U. |
| Generators, power supplies, crystal oscillators: general designation | G |
| Battery of galvanic cells, batteries | G.B. |
| Indicating and signaling devices; general designation | N |
| Sound alarm device | ON |
| Symbolic indicator | H.G. |
| Light signaling device | H.L. |
| Relays, contactors, starters; general designation | TO |
| Devices and elements | letter code |
| Electrothermal relay | kk |
| Time relay | CT |
| Contactor, magnetic starter | km |
| Inductors, chokes; general designation | L |
| Engines, general designation | M |
| Measuring instruments; general designation | R |
| Ammeter (milliammeter, microammeter) | RA |
| Pulse counter | PC |
| Frequency meter | PF |
| Ohmmeter | PR |
| Recording device | PS |
| Action time meter, clock | RT |
| Voltmeter | PV |
| Wattmeter | PW |
| Resistors are constant and variable; general designation | R |
| Thermistor | RK |
| Measuring shunt | R.S. |
| Varistor | RU |
| Switches, disconnectors, short circuits in power circuits (in equipment power supply circuits); general designation | Q |
| Switching devices in control, signaling and measuring circuits; general designation | S |
| Switch or switch | S.A. |
| Push-button switch | S.B. |
| Automatic switch | SF |
| Transformers, autotransformers; general designation | T |
| Electromagnetic stabilizer | T.S. |
| Converters of electrical quantities into electrical ones, communication devices; general designation | And |
| Modulator | ive |
| Demodulator | UR |
| Discriminator | Ul |
| Frequency converter, inverter, frequency generator, rectifier | UZ |
| Semiconductor and electrovacuum devices; general designation | V |
| Diode, zener diode | VD |
| Transistor | VT |
| Thyristor | VS |
| Electrovacuum device | VL |
| Devices and elements | Letter code |
| Microwave lines and elements; general designation | W |
| Coupler | WE |
| Koro tkoea we ka tel | W.K. |
| Valve | W.S. |
| Transformer, phase shifter, heterogeneity | W.T. |
| Attenuator | W.U. |
| Antenna | W.A. |
| Contact connections; general designation | X |
| Pin (plug) | XP |
| Socket (socket) | XS |
| Demountable connection | XT |
| High frequency connector | XW |
| Mechanical devices with electromagnetic drive; general designation | Y |
| Electromagnet | YA |
| Electromagnetic brake | YB |
| Electromagnetic clutch | YC |
| Terminal devices, filters; general designation | Z |
| Limiter | ZL |
| Quartz filter | ZQ |
Table 3. Letter codes for the functional purpose of a radio-electronic device or element.
| Letter code | |
| Auxiliary | A |
| Counting | WITH |
| Differentiating | D |
| Protective | F |
| Test | G |
| Signal | N |
| Integrating | 1 |
| Gpavny | M |
| Measuring | N |
| Proportional | R |
| State (start, stop, limit) | Q |
| Return, reset | R |
| Functional purpose of the device, element | letter code |
| Memorizing, recording | S |
| Synchronizing, delaying | T |
| Speed (acceleration, braking) | V |
| Summing | W |
| Multiplication | X |
| Analog | Y |
| Digital | Z |
Table 4. The most common conventional letter abbreviations in radio electronics, used on various circuits in technical and scientific literature.
| Literal reduction | Decoding abbreviation |
| A.M. | amplitude modulation |
| AFC | automatic frequency adjustment |
| APCG | automatic local oscillator frequency adjustment |
| APChF | automatic frequency and phase adjustment |
| AGC | automatic gain control |
| ARYA | automatic brightness adjustment |
| AC | acoustic system |
| AFU | antenna-feeder device |
| ADC | analog-to-digital converter |
| frequency response | amplitude-frequency response |
| BGIMS | large hybrid integrated circuit |
| NOS | wireless remote control |
| BIS | large integrated circuit |
| BOS | signal processing unit |
| BP | power unit |
| BR | scanner |
| DBK | radio channel block |
| BS | information block |
| BTK | personnel blocking transformer |
| Letter abbreviation | Decoding the abbreviation |
| BTS | blocking transformer line |
| BOO | Control block |
| BC | chroma block |
| BCI | integrated color block (using microcircuits) |
| VD | video detector |
| VIM | time-pulse modulation |
| VU | video amplifier; input (output) device |
| HF | high frequency |
| G | heterodyne |
| GW | playback head |
| GHF | high frequency generator |
| GHF | hyper high frequency |
| GZ | start generator; recording head |
| GIR | heterodyne resonance indicator |
| GIS | hybrid integrated circuit |
| GKR | frame generator |
| GKCH | sweep generator |
| GMW | meter wave generator |
| GPA | smooth range generator |
| GO | envelope generator |
| HS | signal generator |
| Reduction | Decoding the abbreviation |
| GSR | line scan generator |
| gss | standard signal generator |
| yy | clock generator |
| GU | universal head |
| VCO | voltage controlled generator |
| D | detector |
| dv | long waves |
| dd | fractional detector |
| days | voltage divider |
| dm | power divider |
| DMV | decimeter waves |
| DU | remote control |
| DShPF | dynamic noise reduction filter |
| EASC | unified automated communication network |
| ESKD | unified system of design documentation |
| zg | audio frequency generator; master oscillator |
| zs | slowing system; sound signal; pickup |
| AF | audio frequency |
| AND | integrator |
| ICM | pulse code modulation |
| ICU | quasi-peak level meter |
| ims | integrated circuit |
| ini | linear distortion meter |
| inch | infra-low frequency |
| and he | reference voltage source |
| SP | power supply |
| ichh | frequency response meter |
| To | switch |
| KBV | traveling wave coefficient |
| HF | short waves |
| kWh | extremely high frequency |
| KZV | recording-playback channel |
| CMM | pulse code modulation |
| Literal reduction | Decoding the abbreviation |
| kk | frame deflection coils |
| km | coding matrix |
| cnc | extremely low frequency |
| efficiency | efficiency |
| KS | deflection system line coils |
| ksv | standing wave ratio |
| ksvn | voltage standing wave ratio |
| CT | check Point |
| KF | focusing coil |
| TWT | traveling wave lamp |
| lz | delay line |
| fishing | back wave lamp |
| LPD | avalanche diode |
| lppt | tube-semiconductor TV |
| m | modulator |
| M.A. | magnetic antenna |
| M.B. | meter waves |
| TIR | metal-insulator-semiconductor structure |
| MOP | metal-oxide-semiconductor structure |
| ms | chip |
| MU | microphone amplifier |
| neither | nonlinear distortion |
| LF | low frequency |
| ABOUT | common base (switching on a transistor according to a circuit with a common base) |
| VHF | very high frequency |
| oi | common source (turning on the transistor *according to a circuit with a common source) |
| OK | common collector (switching on a transistor according to a circuit with a common collector) |
| onch | very low frequency |
| oos | negative feedback |
| OS | deflection system |
| OU | operational amplifier |
| OE | common emitter (connecting a transistor according to a circuit with a common emitter) |
| Reduction | Decoding the abbreviation |
| Surfactant | surface acoustic waves |
| pds | two-speech set-top box |
| Remote control | remote control |
| pcn | code-voltage converter |
| pnc | voltage-to-code converter |
| PNC | converter voltage frequency |
| village | positive feedback |
| PPU | noise suppressor |
| pch | intermediate frequency; frequency converter |
| ptk | tv channel switch |
| PTS | full TV signal |
| Vocational school | industrial television installation |
| PU | preliminary effort |
| PUV | playback pre-amplifier |
| PUZ | recording pre-amplifier |
| PF | bandpass filter; piezo filter |
| ph | transfer characteristic |
| pcts | full color television signal |
| Radar | line linearity regulator; radar station |
| RP | memory register |
| RPCHG | manual adjustment of local oscillator frequency |
| RRS | line size control |
| PC | shift register; mixing regulator |
| RF | notch or stop filter |
| REA | radio-electronic equipment |
| SBDU | wireless remote control system |
| VLSI | ultra-large scale integrated circuit |
| NE | medium waves |
| SVP | touch program selection |
| Microwave | ultra high frequency |
| sg | signal generator |
| SDV | ultralong waves |
| Reduction | Decoding the abbreviation |
| SDU | dynamic light installation; remote control system |
| SK | channel selector |
| SCR | all-wave channel selector |
| sk-d | UHF channel selector |
| SK-M | meter wave channel selector |
| CM | mixer |
| ench | ultra-low frequency |
| JV | grid field signal |
| ss | clock signal |
| ssi | horizontal clock pulse |
| SU | selector amplifier |
| sch | average frequency |
| TV | tropospheric radio waves; TV |
| TVS | line output transformer |
| tvz | audio output channel transformer |
| tvk | output frame transformer |
| TIT | television test chart |
| TKE | temperature coefficient of capacitance |
| tka | temperature coefficient of inductance |
| tkmp | temperature coefficient of initial magnetic permeability |
| tkns | temperature coefficient of stabilization voltage |
| tks | temperature coefficient of resistance |
| ts | network transformer |
| shopping center | television center |
| tsp | color bar table |
| THAT | technical specifications |
| U | amplifier |
| UV | playback amplifier |
| UVS | video amplifier |
| UVH | sample-hold device |
| UHF | high frequency signal amplifier |
| Literal reduction | Decoding the abbreviation |
| UHF | UHF |
| UZ | recording amplifier |
| Ultrasound | audio amplifier |
| VHF | ultrashort waves |
| ULPT | unified tube-semiconductor TV |
| ULLTST | unified lamp-semiconductor color TV |
| ULT | unified tube TV |
| UMZCH | audio power amplifier |
| CNT | unified TV |
| ULF | low frequency signal amplifier |
| UNU | voltage controlled amplifier. |
| UPT | DC amplifier; unified semiconductor TV |
| HRC | intermediate frequency signal amplifier |
| UPCHZ | intermediate frequency signal amplifier? |
| UPCH | intermediate frequency image amplifier |
| URCH | radio frequency signal amplifier |
| US | interface device; comparison device |
| USHF | microwave signal amplifier |
| USS | horizontal sync amplifier |
| USU | universal touch device |
| UU | control device (node) |
| UE | accelerating (control) electrode |
| UEIT | universal electronic test chart |
| PLL | phase automatic frequency control |
| Literal reduction | Decoding the abbreviation |
| HPF | high pass filter |
| FD | phase detector; photodiode |
| FIM | pulse phase modulation |
| FM | phase modulation |
| LPF | low pass filter |
| FPF | intermediate frequency filter |
| FPCHZ | audio intermediate frequency filter |
| FPCH | image intermediate frequency filter |
| FSI | lumped selectivity filter |
| FSS | concentrated selection filter |
| FT | phototransistor |
| FCHH | phase-frequency response |
| DAC | digital-to-analog converter |
| Digital computer | digital computer |
| CMU | color and music installation |
| DH | central television |
| BH | frequency detector |
| CHIM | pulse frequency modulation |
| world championship | frequency modulation |
| shim | pulse width modulation |
| shs | noise signal |
| ev | electron volt (e.V) |
| COMPUTER. | electronic computer |
| emf | electromotive force |
| ek | electronic switch |
| CRT | cathode-ray tube |
| AMY | electronic musical instrument |
| emos | electromechanical feedback |
| EMF | electromechanical filter |
| EPU | record player |
| Digital computer | electronic digital computer |
Literature: V.M. Pestrikov. Encyclopedia of amateur radio.
While working on electrical engineering, a person may come across symbols of elements that are conventionally marked on electrical wiring diagrams. The variety of electrical circuits is very wide. They have different functions and classifications. But all graphic symbols are conventionally reduced to the same forms, and for all schemes the elements correspond to each other.
An electrical wiring diagram is a document that indicates the connections between the constituent elements of different devices that consume electricity according to certain standard rules. Such an image in the form of a drawing is intended to teach electrical installation specialists so that they understand from the diagram the principle of operation of the device, and from what components and elements it is assembled.
The main purpose of the wiring diagram is to assist in the installation of electrical devices and instruments, simple and easy detection of faults in the electrical circuit. Next, we will understand the types and types of electrical wiring diagrams, find out their properties and characteristics of each type.
All electrical diagrams, like documents, are divided into types and types. According to the relevant standards, you can find a division of these documents by types of schemes and types. Let us analyze their detailed classification.
Considering the electrical diagrams, the listed designations, the type and type are determined by the name of the electrical diagram.
In the modern period, both domestic and imported elements are used in electrical installation work. Foreign parts can be represented in a wide range. In diagrams and drawings they are also designated conventionally. Not only the size of the parameters is described, but also the list of elements included in the device and their relationship.
Now you need to figure out what each specific electrical circuit is intended for and what it consists of.
This type is used in distribution networks. It provides full disclosure of the operation of electrical equipment. The drawing must indicate the functional units and their connections. The diagram has two types: single-line, complete. The single-line diagram shows the primary networks (power). Here is her example:
The full version of the electrical circuit is depicted in elemental or expanded form. If the device is simple, and the drawing includes all the explanations, then a detailed plan will suffice. For a complex device with a control circuit, measurement, etc., the optimal solution would be to depict all the nodes on separate sheets to avoid confusion.
There is also a schematic electrical diagram, which shows a copy of the plan with the designation of a separate unit, its composition and operation.
Such electrical diagrams are used to explain the installation of any wiring. They can depict the exact position of the elements, their connection, and the characteristics of the installations. The apartment wiring diagram will show the placement of sockets, lamps, etc.
This diagram guides the electrical installation work and gives an understanding of all connections. For the installation of household devices, this scheme is better suited for operation.
This type of diagram includes different types and types of documents. It is used in order not to clutter the drawing and to indicate important circuits and features. More often, integrated schemes are used in industrial enterprises. For home use it hardly makes sense.
Having studied the symbols and prepared the necessary documentation, it is not difficult to understand the operation of any electrical installation.
The most difficult task for an electrician is understanding the interaction of elements in a circuit. You need to know how to read and assemble a diagram. Assembly requires certain rules:
After completing the assembly, a closed circuit must be formed. As an example, let’s look at connecting a chandelier consisting of 3 shades at home using a double switch.
First, let's determine the operating procedure of the chandelier. When you turn on the 1st key, one light should light up, if you turn on the 2nd key, then the other two. According to the diagram, there are 3 wires going to the switch and the chandelier. There are two wires coming from the network, phase and neutral.
Using the indicator, we identify and find the phase, connect it to the switch without interrupting the zero. We connect the wire to the common terminal of the switch. 2 wires will go from it to 2 circuits. Connect one of the wires to the lamp socket. We take out the second conductor from the cartridge and connect it to zero. One chain is ready. To check, click the first button of the switch, the lamp lights up.
We connect the 2nd wire from the switch to the socket of another lamp. We connect the wire from the cartridge to zero. If you click the switch keys in turn, different lamps will light up.
Now let's connect the third lamp. We connect it in parallel to any lamp. In the chandelier one wire became common. It is made distinctive by color. If your wires are all the same color, then to avoid confusion, you must use an indicator during installation. Connecting a chandelier usually does not require much work, since this circuit is not particularly complicated.
"How to read electrical diagrams?" Perhaps this is the most frequently asked question on the RuNet. If in order to learn to read and write, we studied the alphabet, then here it is almost the same. 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 GOST version of the designation of radioelements.
Electrical ladder drawings are still one of the common and reliable tools used to troubleshoot equipment when it fails. Like any good troubleshooting tool, you should be familiar with its basic functions in order to get the most out of the chart in this area. In other words, having a basic understanding of how a diagram is laid out and the meaning of the numbers and symbols found on the diagram will make you a much more proficient service technician.
Typically, there are two separate parts of the ladder design: the power component and the control component. The power section consists of elements such as the motor, motor starter and overload contacts, disconnectors and protective devices. The control part includes the elements that make the power components do their job. For this discussion, we will focus on the control portion of the drawing. Let's take a look at the most common components.
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.
For example, in an air compressor system there will be a symbol for a pressure switch. If a person performing troubleshooting and repair does not recognize this symbol, it will be difficult to locate the switch to determine whether it is working properly. In many cases, input devices are considered to be either normally open or normally closed. Normally open or closed status refers to the complete state of the device. If the device is normally closed, a resistance test will give a reading. The normally open and normally closed states of the devices are not marked on the ladder drawing.
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.
Rather, you must recognize the symbol. A useful hint for determining whether contacts are open or closed is to think of them in terms of gravity. If the device is subject to gravity, its normal state is shown in the drawing. An exception to this concept is found in devices containing springs. For example, when drawing a normally open button, it appears that the button should fall and close. However, there is a spring in the button that holds the contacts in the open position.
So, it seems that we have decided on the task of this scheme. Straight lines are wires through which electric current will flow. Their task is to connect radioelements.
The point where three or more wires connect is called knot. We can say that this is where the wires are soldered:
Control voltage and safety. The control voltage for the system can come from a control transformer, which is supplied from the power section of the drawing or other source. For safety reasons, it is important to determine the control voltage source before working on the system because the power switch cannot turn off the control voltage, so an electrically safe state will not be established.
The drawing is called a staircase drawing because it resembles a staircase as it is constructed and presented on paper. The two vertical lines that serve as the boundary for the control system and deliver control voltage to the devices are called rails. Rails may have overcurrent devices in them and may have contacts from control devices. These reference lines may be thicker than others to better identify them.
If you look closely at the diagram, you can see the intersection of two wires
Such intersection will often appear in diagrams. Remember once and for all: in this place the wires are not connected and they must be isolated from each other. In modern circuits, you can most often see this option, which already visually shows that there is no connection between them:
Like a real staircase, the rails support the steps. If a staircase pattern runs across multiple pages, the control voltage is transferred from one page to the next along the rails. There are several ways that can be represented in the drawing. The page number on which the rails continue should be noted.
In this circuit arrangement, the sequence of events can be described as such. When the button is pressed, the circuit is completed and current will flow to activate the coil. Steps. Ladder rungs are made up of wires and input devices that either allow current to flow or interrupt current to output devices. These lines may be thin lines compared to the lines of the rails. From the placement of input and output devices, you can determine the sequence of events that either activate or de-energize the outputs.
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:
The key to good troubleshooting is identifying this sequence of events. Input devices are typically located on the left side of the stage, and output devices are located on the right. Placement of input devices. The input devices are placed on the steps in a manner that indicates the current flow through the string when there is a full path to the outputs. There are several ways in which these input devices can be placed on steps, although as stated earlier they are usually located on the left side.
This means that they are placed from end to end on the drawing. They must be in the closed position for current to flow through them. Understanding this flow is a great troubleshooting aid. The key question you always ask yourself is: “What does it take to activate the output?”
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 stands for resistor. Since it is not the only one in our circuit, the developer of this circuit gave it 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 nominal value is 10 KiloOhms. Well, something like this...
Here is a simple example for analysis. By following the path for the current one, you can see the logic for placing input devices. This logic determines the decision making process of input devices and the path for current as it flows out. Logical operators. There are several logical operators that can be used when placing input devices in steps. Figure 3 shows all three.
The start button starts the path and activates the reel. . Placement of output devices. As noted earlier, the output devices are placed on the right side of the stair drawing. Unlike input devices, it is important that output devices are placed in parallel. If they are placed in series, electrical theory states that the voltage will drop across the resistance of each output. If this happens, they will not work properly.
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.
Outputs include items such as lights, coils, solenoids, and heating elements. In addition to the conventional symbols shown in FIG. 1, letters and numbers also help identify output devices. Typically coils have pins connected to them. These pins will change state when the coil is activated. Changing contacts will either complete or open the way for the current one.
As noted in FIG. 4, when the button is pressed, the path is completed and current will flow to activate the coil. When a coil is activated, the contacts associated with the coil will change state. The red light will be on and the green light will go off. Location of contacts. In a staircase drawing, the contacts associated with the coil can be located using a cross-reference system. The steps are usually numbered on the left side of the rail. The number on the right side of the rail refers to the contacts associated with the coil.
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
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 meter
B.C. - selsyn sensor
D.A. - analog integrated circuit
DD - integrated digital circuit, logical element
D.S. - information storage device
D.T. - delay device
EL - lighting lamp
E.K. - a heating element
F.A. - instantaneous current protection element
FP - inertial current protection element
F.U. - fuse
F.V. - voltage protection element
G.B. - battery
H.G. - 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 switch
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. - switches activated by rotation speed
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 - electric vacuum device
VS - thyristor
VT - transistor
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
Well, now the most interesting thing: the graphic designation of radioelements.
I will try to give the most common designations of elements used in the diagrams:
Resistors are constant
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
Varistor
Shunt
Capacitors
a) general designation of a capacitor
b) varicond
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) Light-emitting diode
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 switching contacts (switching contacts can be separated in the circuit from the relay coil)
Circuit breakers
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
Field effect transistor with control P-N junction
Those who have just started studying electronics are faced with the question: “How to read circuit diagrams?” The ability to read circuit diagrams is necessary when independently assembling an electronic device and more. What is a circuit diagram? A circuit diagram is a graphical representation of a set of electronic components connected by current-carrying conductors. The development of any electronic device begins with the development of its circuit diagram.
It is the circuit diagram that shows exactly how radio components need to be connected in order to ultimately obtain a finished electronic device that is capable of performing certain functions. To understand what is shown on the circuit diagram, you first need to know the symbols of the elements that make up the electronic circuit. Any radio component has its own conventional graphic designation - UGO . As a rule, it displays a structural device or purpose. For example, the conventional graphic designation of the speaker very accurately conveys the real structure of the speaker. This is how the speaker is indicated in the diagram.
Agree, very similar. This is what the resistor symbol looks like.
A regular rectangle, inside of which its power can be indicated (In this case, a 2 W resistor, as evidenced by two vertical lines). But this is how a regular capacitor of constant capacity is designated.
These are fairly simple elements. But semiconductor electronic components, such as transistors, microcircuits, triacs, have a much more sophisticated image. So, for example, any bipolar transistor has at least three terminals: base, collector, emitter. In the conventional image of a bipolar transistor, these terminals are depicted in a special way. To distinguish a resistor from a transistor in a diagram, first you need to know the conventional image of this element and, preferably, its basic properties and characteristics. Since each radio component is unique, certain information can be encrypted graphically in a conventional image. For example, it is known that bipolar transistors can have different structures: p-n-p or n-p-n. Therefore, the UGO of transistors of different structures are somewhat different. Take a look...
Therefore, before you begin to understand the circuit diagrams, it is advisable to get acquainted with radio components and their properties. This will make it easier to understand what is shown in the diagram.
Our website has already talked about many radio components and their properties, as well as their symbols on the diagram. If you forgot, welcome to the “Start” section.
In addition to conventional images of radio components, other clarifying information is indicated on the circuit diagram. If you look closely at the diagram, you will notice that next to each conventional image of a radio component there are several Latin letters, for example, VT , B.A. , C etc. This is an abbreviated letter designation for a radio component. This was done so that when describing the operation or setting up a circuit, one could refer to one or another element. It is not difficult to notice that they are also numbered, for example, like this: VT1, C2, R33, etc.
It is clear that there can be as many radio components of the same type in a circuit as desired. Therefore, to organize all this, numbering is used. The numbering of parts of the same type, for example resistors, is carried out on circuit diagrams according to the “I” rule. This is, of course, just an analogy, but a pretty clear one. Take a look at any diagram, and you will see that the same type of radio components on it are numbered starting from the upper left corner, then in order the numbering goes down, and then again the numbering starts from the top, and then down, and so on. Now remember how you write the letter “I”. I think this is all clear.
What else can I tell you about the concept? Here's what. The diagram next to each radio component indicates its main parameters or standard rating. Sometimes this information is presented in a table to make the circuit diagram easier to understand. For example, next to the image of a capacitor, its nominal capacity in microfarads or picofarads is usually indicated. The rated operating voltage may also be indicated if this is important.
Next to the UGO of the transistor, the type rating of the transistor is usually indicated, for example, KT3107, KT315, TIP120, etc. In general, for any semiconductor electronic components such as microcircuits, diodes, zener diodes, transistors, the type rating of the component that is supposed to be used in the circuit is indicated.
For resistors, usually only their nominal resistance is indicated in kilo-ohms, ohms or mega-ohms. The rated power of the resistor is encrypted with oblique lines inside the rectangle. Also, the power of the resistor may not be indicated on the diagram and on its image. This means that the power of the resistor can be any, even the smallest, since the operating currents in the circuit are insignificant and even the lowest-power resistor produced by industry can withstand them.
Here is the simplest circuit of a two-stage audio amplifier. The diagram shows several elements: battery (or just battery) GB1 ; fixed resistors R1 , R2 , R3 , R4 ; power switch SA1 , electrolytic capacitors C1 , C2 ; fixed capacitor C3 ; high impedance speaker BA1 ; bipolar transistors VT1 , VT2 structures n-p-n. As you can see, using Latin letters I refer to a specific element in the diagram.
What can we learn by looking at this diagram?
Any electronics operates on electric current, therefore, the diagram must indicate the current source from which the circuit is powered. The current source can be a battery and an AC power supply or a power supply.
So. Since the amplifier circuit is powered by DC battery GB1, therefore, the battery has a polarity of plus “+” and minus “-”. In the conventional image of the power battery, we see that the polarity is indicated next to its terminals.
Polarity. It is worth mentioning separately. For example, electrolytic capacitors C1 and C2 have polarity. If you take a real electrolytic capacitor, then on its body it is indicated which of its terminals is positive and which is negative. And now, the most important thing. When assembling electronic devices yourself, it is necessary to observe the polarity of connecting electronic parts in the circuit. Failure to follow this simple rule will result in the device not working and possibly other undesirable consequences. Therefore, do not be lazy from time to time to look at the circuit diagram according to which you assemble the device.
The diagram shows that to assemble the amplifier you will need fixed resistors R1 - R4 with a power of at least 0.125 W. This can be seen from their symbol.
You can also notice that the resistors R2* And R4* marked with an asterisk * . This means that the nominal resistance of these resistors must be selected in order to establish optimal operation of the transistor. Usually in such cases, instead of resistors whose value needs to be selected, a variable resistor with a resistance slightly greater than the value of the resistor indicated on the diagram is temporarily installed. To determine the optimal operation of the transistor in this case, a milliammeter is connected to the open circuit of the collector circuit. The place on the diagram where you need to connect the ammeter is indicated on the diagram like this. The current that corresponds to the optimal operation of the transistor is also indicated.
Let us recall that to measure current, an ammeter is connected to an open circuit.
Next, turn on the amplifier circuit with switch SA1 and begin to change the resistance with a variable resistor R2*. At the same time, they monitor the ammeter readings and ensure that the milliammeter shows a current of 0.4 - 0.6 milliamps (mA). At this point, setting the mode of transistor VT1 is considered complete. Instead of the variable resistor R2*, which we installed in the circuit during setup, we install a resistor with a nominal resistance that is equal to the resistance of the variable resistor obtained as a result of setup.
What is the conclusion from this whole long story about getting the circuit working? And the conclusion is that if in the diagram you see any radio component with an asterisk (for example, R5*), this means that in the process of assembling the device according to this circuit diagram, it will be necessary to adjust the operation of certain sections of the circuit. How to set up the operation of the device is usually mentioned in the description of the circuit diagram itself.
If you look at the amplifier circuit, you will also notice that there is such a symbol on it.
This designation indicates the so-called common wire. In technical documentation it is called a housing. As you can see, the common wire in the amplifier circuit shown is the wire that is connected to the negative “-” terminal of the power battery GB1. For other circuits, the common wire may also be the wire that is connected to the plus of the power source. In circuits with bipolar power supply, the common wire is indicated separately and is not connected to either the positive or negative terminal of the power source.
Why is “common wire” or “housing” indicated on the diagram?
All measurements in the circuit are carried out with respect to the common wire, with the exception of those that are specified separately, and peripheral devices are also connected with respect to it. The common wire carries the total current consumed by all elements of the circuit.
The common wire of a circuit is in reality often connected to the metal housing of an electronic device or a metal chassis on which printed circuit boards are mounted.
It is worth understanding that the common wire is not the same as the ground. " Earth" - this is grounding, that is, an artificial connection to the ground through a grounding device. It is indicated in the diagrams as follows.
In some cases, the common wire of the device is connected to ground.
As already mentioned, all radio components in the circuit diagram are connected using current-carrying conductors. The current-carrying conductor can be a copper wire or a copper foil track on a printed circuit board. A current-carrying conductor in a circuit diagram is indicated by a regular line. Like this.
The places where these conductors are soldered (electrically connected) to each other or to the terminals of radio components are depicted as a bold dot. Like this.
It is worth understanding that on a circuit diagram, a dot only indicates the connection of three or more conductors or terminals. If the diagram shows the connection of two conductors, for example, the output of a radio component and a conductor, then the diagram would be overloaded with unnecessary images and at the same time its informativeness and conciseness would be lost. Therefore, it is worth understanding that a real circuit may contain electrical connections that are not shown on the circuit diagram.
The next part will talk about connections and connectors, repeating and mechanically coupled elements, shielded parts and conductors. Click " Further"...
Electrical diagrams are a graphical representation of components, mutual connections, connections of electrical devices, and installations. Diagrams help you see and understand how an electrical installation or device works. In case of repair, having a diagram makes troubleshooting and troubleshooting much easier. Wiring diagrams do not provide information about the operation of the device; they are intended for its assembly. The ability to read various electrical diagrams is important for both beginners and experienced specialists; it is necessary during assembly, installation and maintenance, and troubleshooting.
In accordance with GOST 2.701-2008 “Unified system of design documentation (ESKD). Scheme. Types and types. General requirements for implementation" electrical circuits are assigned a type code designation with the letter "E".
The table shows the types of circuits regulated by GOST.
| Circuit type | Definition | Circuit type code |
| Structural | A document defining the main functional parts of the product, their purpose and relationships | 1 |
| Functional | A document explaining the processes occurring in individual functional circuits of the product (installation) or the product (installation) as a whole | 2 |
| Fundamental (full) | A document that defines the full composition of elements and the relationships between them and, as a rule, gives a complete (detailed) understanding of the principles of operation of the product (installation) | 3 |
| Connection diagram (installation) | A document showing the connections of the component parts of the product (installation) and defining the wires, harnesses, cables or pipelines by which these connections are made, as well as the places of their connections and input (connectors, boards, clamps, etc.) | 4 |
| Connections | Document showing external connections of the product | 5 |
| General | A document defining the components of the complex and their connections to each other at the site of operation | 6 |
| Locations | A document defining the relative location of the components of the product (installation), and, if necessary, also bundles (wires, cables), pipelines, optical fibers, etc. | 7 |
| United | A document containing elements of different types of circuits of the same type | 0 |
The drawing code consists of a letter, in our case it is the letter “E” and a digital part that determines the type, according to Table 1. For example, E1 is an electrical structural diagram, E5 is a diagram showing the external connections of the product.
You need to start by studying conventional graphic symbols (CGI). The designations on the drawings have a standard appearance and are regulated by GOSTs, for example, GOST 21.210-2014, GOST 2.755-87, GOST 2.721, GOST 2.756-76 and a number of others. Image standards apply to all elements, including connections between them, installation methods, laying, etc.
In some cases, GOST allows deviations from standards. For example, when drawing up structural combined diagrams, non-standard or close-to-real images of objects and photographs are often used, accompanying them with descriptions with brief explanations, as in the diagram of a telephone set.
But in general, they try to comply with the standards so as not to introduce discrepancies and confusion into the documentation, especially when it comes to serious projects for industrial enterprises.
Large images are divided into parts, indicating links to other sheets or indicating connections. The initial position of relay contacts, buttons, coils is shown in the absence of voltage, this is the standard.
Let's consider the above using the example of a basic relay circuit for controlling a conveyor.
There are two functional parts: a power part, consisting of motor power circuits, and a relay, which is designed to control the power part.
The power part consists of:
The phases are designated by the Latin letters A, B, C. Since three-phase power is used, the contacts of the circuit breaker and contactor are mechanically connected to simultaneously turn on/off all three phases.
The relay part contains:
Connecting lines represent electrical connections between elements. The intersecting lines are not connected to each other. Alternatively, the lack of connection is indicated by an arc symbol. The presence of a connection is indicated by a point at the intersection or junction.
Contacts of relays, switches and other switching devices have two states:
Accordingly, when voltage is applied to the relay or contactor coil, the relay will be attracted and the state of the contacts will change to the opposite. The same thing will happen with the button and the circuit breaker; when it is turned on, the state of the contact changes.
Depends on their construction and purpose of use. The flow of current in electrical circuits begins and ends at the power source. If this is a direct current source, then from plus to minus, if alternating, then from the phase wire to the neutral wire or between phases. You can start reading both from the power source and from the load. The power circuit from the source reads like this:
Diagrams are often read in reverse order when troubleshooting. For example, our engine does not turn on.
From there you can start looking for reasons for turning off the contactor. This can be either turning off the 2-QF machine, or turning off the 2-KM coil, which is turned on by a relay circuit. Thus, reading electrical drawings is similar to reading books, following the path of current flow from element to element.
The relay part looks somewhat more complicated, but if we look at it in parts and move sequentially, step by step, it is not difficult to understand the logic of its operation. Complex circuits always consist of several separate functional units. Having dealt with the individual fragments and connections between them, a complete picture of the operation of the entire circuit emerges.
For example, in this circuit there is a testing unit for light signaling. It consists of a 2-SB4 button and diodes connected to the HL signal lamps. The button is connected to the “+” of the 24V 2-GB power supply with a normally open contact. All lamps are permanently connected to the “-” power source. When the button is pressed, the circuit is closed through contact 2-SB4, diodes, lamps. As a result, all 4 lamps light up. In this way, their serviceability is visually determined. When the button is released, the circuit breaks and the lamps go out.
The sound alarm testing unit 2-HA1, 2-HA2 works in a similar way with the button 2-SB5. Even though these nodes are on the same drawing and connected to other parts, they are separately functioning complete circuits.
The main control circuit assembles the chains of the tape relay, emergency stop, readiness, and after a time delay determined by the 2-KT time relay, relay 2-K7 with its contact turns on the 2-KM power contactor, which starts the 2-W engine.
Knowledge of graphic symbols, like the alphabet for reading books, is the main condition for reading diagrams. But the alphabet alone is not enough for reading; you need to be able to connect letters into words, and words into meaning. Understanding the operation of a circuit diagram is impossible without understanding the operating principle of the devices from which it is assembled. So, if a person does not understand how an electromagnetic relay or timer works, he will not be able to understand what will happen when voltage is applied to one or another part of the circuit. Thus, circuit design is inextricably linked with the study of the material part of electrical equipment.
The schematic diagram was discussed above. In a special case, such as installation, it is not necessary to imagine how it works. For this purpose, special installation drawings are produced, which indicate which wire connects which terminals.
Wires with terminals must be numbered. During installation, you just need to carefully monitor what is connected to what in order to correctly assemble the device and installation.
A qualified specialist must be able to understand all types of drawings. Despite standardization, there are a huge number of differences and diversity in the rules for constructing electrical circuits produced by various manufacturers and design departments. It is very important to know the principles of operation of electrical equipment and the devices that make up the circuit. The ability to read and understand diagrams is a multifaceted process that requires patience and time.
