To be able to assemble an electronic device, you need to know the designation of radio components on the diagram and their name, as well as the order of their connection. To achieve this goal, schemes were invented. At the dawn of radio engineering, radio components were depicted in three dimensions. Their compilation required the experience of the artist and knowledge of the appearance of the parts. Over time, the images were simplified until they turned into conventional signs.
The circuit itself, on which the conventional graphic symbols (UGO) are drawn, is called principal. It not only shows how certain elements of the circuit are connected, but also explains how the entire device works, showing the principle of its operation. To achieve this, it is important to correctly show the individual groups of elements and the connection between them.
In addition to the principle, there are also assembly ones. They are designed to accurately display each element in relation to each other. The arsenal of radioelements is huge. New ones are constantly added. Nevertheless, UGO is almost the same on all schemes, but the letter code is significantly different. There are 2 types of standard:
- state, this standard may include several states;
- international, enjoyed almost all over the world.
But whatever standard is used, it must clearly show the designation of radio components on the diagram and their name. Depending on the functionality of the radio components of the UGO, they can be simple or complex. For example, several conditional groups can be distinguished:
- power supplies;
- indicators, sensors;
- switches;
- semiconductor elements.
This list is incomplete and serves only for clarity. To make it easier to understand the symbols of radio components on the diagram, you need to know the principle of operation of these elements.
Power supplies
These include all devices capable of generating, storing or converting energy. The first battery was invented and demonstrated by Alexandro Volta in 1800. It was a set of copper plates lined with wet cloth. The modified drawing began to consist of two parallel vertical lines, between which there is an ellipsis. It replaces the missing plates. If the power supply consists of one element, the ellipsis is not used.
In a DC circuit, it is important to know where the positive voltage is. Therefore, the positive plate is made higher and the negative one is lower. Moreover, the designation of the battery on the diagram and the battery is no different.
There is also no difference in the letter code Gb. Solar panels, which generate current under the influence of sunlight, in their UGO have additional arrows directed towards the battery.
If the power supply is external, for example, the radio circuit is powered from the mains, then the power input is indicated by terminals. It can be arrows, circles with all sorts of additions. They indicate the rated voltage and type of current. Alternating voltage is indicated by a "tilde" and the letter code Ac may be. For direct current, the positive input is "+", the negative "-", or there may be a "common" sign. It is denoted by an inverted T.
Semiconductors, perhaps, have the most extensive nomenclature in electronics. More devices are added gradually. All of them can be roughly divided into 3 groups:
- Diodes.
- Transistors.
- Microcircuits.
In semiconductor devices, a pn-junction is used, circuitry in UGO tries to show the features of a particular device. So, a diode is capable of passing current in one direction. This property is shown schematically in the legend. It is made in the form of a triangle with a dash at the top. This dash shows that the current can only flow in the direction of the triangle.
If a short segment is attached to this straight line and it is facing in the opposite direction from the direction of the triangle, then this is already a zener diode. It is capable of passing a small current in the opposite direction. This designation is only valid for general purpose devices. For example, the image for a Schottky barrier diode is drawn with an s-shaped sign.
Some radio parts have the properties of two simple devices connected together. This feature is also noted. When displaying a double-sided zener diode, both are drawn, with the tops of the triangles pointing towards each other. When designating a bidirectional diode, 2 parallel diodes are depicted, directed in different directions.
Other devices have the properties of two different parts, such as a varicap. It is a semiconductor, so it is drawn with a triangle. However, the capacity of its pn junction is mainly used, and these are already the properties of a capacitor. Therefore, a capacitor sign is attached to the apex of the triangle - two parallel straight lines.
Signs of external factors affecting the device are also reflected. A photodiode converts sunlight into electrical current, some types are solar cells. They are depicted as a diode, only in a circle, and 2 arrows are directed at them to show the sun's rays. The LED, on the other hand, emits light, so the arrows come from the diode.
Polar and bipolar transistors
Transistors are also semiconductors, but have basically two pnp junctions in bipolar transistors. The middle area between the two transitions is the control area. The emitter injects charge carriers and the collector receives them.
The body is shown in a circle. Two p-n junctions are shown as one segment in this circle. On the one hand, a straight line at an angle of 90 degrees approaches this segment - this is the base. On the other hand, 2 oblique lines. One of them has an arrow - this is an emitter, the other without an arrow - a collector.
The emitter determines the structure of the transistor. If the arrow goes in the direction of the junction, then this is a p-n-p type transistor, if from it, then it is an n-p-n transistor. Previously, a single-junction transistor was produced, it is also called a two-base diode, it has one p-n-junction. It is designated as bipolar, but there is no collector, and there are two bases.
A field-effect transistor has a similar pattern. The difference is that the transition is called a channel. A straight line with an arrow approaches the channel at a right angle and is called a shutter. On the opposite side, the drain and source are suitable. The direction of the arrow indicates the type of channel. If the arrow is directed to the channel, then the channel is n-type, if from it, then the p-type.
The insulated gate field effect transistor has some differences. The gate is drawn in the form of the letter g and is not connected to the channel, the arrow is placed between the drain and the source and has the same meaning. In transistors with two insulated gates, a second such gate is added in the circuit. The drain and source are interchangeable, so the field-effect transistor can be connected as you like, you just need to connect the gate correctly.
Integrated Circuits
Integrated circuits are the most complex electronic components. Conclusions are usually part of the overall scheme ... They can be divided into the following types:
- analog;
- digital;
- analog-digital.
On the diagram, they are indicated as a rectangle. Inside is the code and (or) the name of the circuit. Outgoing leads are numbered. Op-amps are drawn with a triangle, the output signal comes from its top. To count the pins, a mark is placed on the microcircuit case next to the first pin. This is usually a square notch. To correctly read the microcircuits and symbol designations, tables are attached.
Other elements
All radio components are interconnected by conductors. On the diagram, they are depicted by straight lines and are drawn strictly horizontally and vertically. If the conductors, when crossing each other, have an electrical connection, then a dot is put in this place. In Soviet and American schemes, to show that the conductors do not connect, a semicircle is placed at the intersection.
Capacitors are indicated by two parallel sections. If it is electrolytic, for the connection of which it is important to observe the polarity, then a + is placed near its positive terminal. There may be designations of electrolytic capacitors in the form of two parallel rectangles, one of them (negative) is colored black.
An arrow is used to indicate variable capacitors; it crosses out the capacitor diagonally. Trimmers use a T-sign instead of an arrow. Varikond - a capacitor that changes the capacitance from the applied voltage, is drawn, like a variable, but the arrow is replaced by a short straight line, near which the letter u stands. The capacitance is indicated by a number and μF (microFarad) is placed next to it. If the capacity is less, the letter code is omitted.
Another element that no electrical circuit can do without is a resistor. It is indicated in the diagram as a rectangle. To show that the resistor is variable, an arrow is drawn from above. It can be connected either to one of the pins, or it can be a separate pin. For trimmers, a sign in the form of the letter t is used. As a rule, its resistance is indicated next to the resistor.
Dash symbols can be used to indicate the power of fixed resistors. A power of 0.05 W is indicated by three oblique, 0.125 W - two oblique, 0.25 W - one oblique, 0.5 W - one longitudinal. High power is shown in Roman numerals. Due to the variety, it is impossible to describe all the designations of electronic components on the diagram. To determine this or that radioelement, use reference books.
Alphanumeric code
For simplicity, radio components are divided into groups according to features. Groups are divided into types, types - into types. Below are the group codes:
For ease of installation, the locations for radio components are indicated on printed circuit boards by letter code, drawing and numbers. For parts with polar leads, a + is put at the positive lead. In places for soldering transistors, each pin is marked with a corresponding letter. Fuses and shunts are shown as a straight line. The conclusions of the microcircuits are marked with numbers. Each element has its own serial number, which is indicated on the board.
Any electrical circuits can be presented in the form of drawings (schematic and wiring diagrams), the design of which must comply with the ESKD standards. These standards apply to both wiring or power circuits and electronic devices. Accordingly, in order to "read" such documents, it is necessary to understand the symbols in the electrical circuits.
Regulations
Given the large number of electrical elements, for their alphanumeric (hereinafter BO) and conventionally graphic designations (UGO), a number of normative documents have been developed to exclude discrepancy. Below is a table showing the main standards.
Table 1. Standards for the graphic designation of individual elements in installation and circuit diagrams.
| GOST number | Short description |
| 2.710 81 | This document contains the requirements of GOST for BO of various types of electrical elements, including electrical appliances. |
| 2.747 68 | Requirements for the size of displaying elements in graphical form. |
| 21.614 88 | Accepted standards for electrical plans and wiring. |
| 2.755 87 | Display on diagrams of switching devices and contact connections |
| 2.756 76 | Standards for sensing parts of electromechanical equipment. |
| 2.709 89 | This standard regulates the standards according to which the contact connections and wires are indicated on the diagrams. |
| 21.404 85 | Schematic symbols for equipment used in automation systems |
It should be borne in mind that the element base changes over time, accordingly, changes are made to the regulatory documents, although this process is more inert. Let's give a simple example, RCDs and difavtomats have been widely used in Russia for more than a decade, but there is still no single standard for these devices in accordance with GOST 2.755-87, in contrast to circuit breakers. It is quite possible that this issue will be settled in the near future. To keep abreast of such innovations, professionals track changes in regulatory documents, amateurs do not need to do this, it is enough to know the decoding of the main designations.
Types of electrical circuits
In accordance with the norms of ESKD, diagrams mean graphic documents on which, using the accepted designations, the main elements or nodes of the structure are displayed, as well as the links that unite them. According to the accepted classification, ten types of circuits 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 the elements are shown, then - complete.
If the wiring of the apartment is displayed on the drawing, then the locations of the lighting fixtures, sockets and other equipment are indicated on the plan. Sometimes you can hear how such a document is called a power supply scheme, this is incorrect, since the latter reflects the way consumers are connected to a substation or other power source.
Having dealt with the electrical circuits, we can proceed to the designations of the elements indicated on them.
Graphic symbols
Each type of graphic document has its own designations, regulated by the relevant normative documents. Let's give as an example the main graphic symbols for different types of electrical circuits.
Examples of UGO in functional diagrams
Below is a figure depicting the main nodes of automation systems.
Examples of symbols for electrical appliances and automation equipment in accordance with GOST 21.404-85 Description of designations:
- A - Basic (1) and allowed (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 console or electrical panel.
- С - Display of executive mechanisms (MI).
- D - Influence of IM on the regulatory body (hereinafter RO) when the power is turned off:
- Opening of RO
- Closing RO
- The position of the RO remains unchanged.
- E - IM, which additionally has a manual drive. This symbol can be used for any position of the RO specified in clause D.
- F- Received communication lines display:
- General.
- No connection when crossing.
- Connected when crossing.
UGO in single-line and complete wiring diagrams
There are several groups of symbols for these schemes, we will give the most common ones. For complete information, you need to refer to the regulatory documents, the numbers of state standards will be given for each group.
Power supplies.
The symbols shown in the figure below are used for their designation.
UGO power supplies on schematic diagrams (GOST 2.742-68 and GOST 2.750.68) Description of designations:
- A - source with constant voltage, its polarity is indicated by symbols "+" and "-".
- V is the electricity icon representing alternating voltage.
- C - the symbol of AC and DC voltage, used in cases where the device can be powered from any of these sources.
- D - Display battery or galvanic power supply.
- E- Symbol for a multi-cell battery.
Communication lines
The basic elements of electrical connectors are shown below.
Designation of communication lines on schematic diagrams (GOST 2.721-74 and GOST 2.751.73) Description of designations:
- 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 - Earth symbol.
- E - Electrical connection with the device body.
- F - On complex diagrams, from several component parts, a break in communication is thus indicated, in such cases "X" is information about where the line will be extended (as a rule, the element number is indicated).
- G - Intersection with no connection.
- H - Connection at the intersection.
- I - Branches.
Designation of electromechanical devices and contact connections
Examples of designation of magnetic starters, relays, as well as contacts of communication devices can be found below.
UGO, adopted for electromechanical devices and contactors (GOST 2.756-76, 2.755-74, 2.755-87) Description of designations:
- A - symbol of the coil of an electromechanical device (relay, magnetic starter, etc.).
- B - UGO of the receiving part of the electrical thermal protection.
- C - displays the coil of the device with mechanical interlock.
- D - contacts of switching devices:
- Closing.
- Openers.
- Switching.
- E - Symbol for designation of manual switches (buttons).
- F - Group switch (switch).
UGO electric machines
Here are some examples of displaying electrical machines (hereinafter EM) in accordance with the current standard.
Designation of electric motors and generators on schematic diagrams (GOST 2.722-68) Description of designations:
- A - three-phase EM:
- Asynchronous (short-circuited rotor).
- Same as point 1, only in two-speed version.
- Asynchronous EMs with phase rotor design.
- Synchronous motors and generators.
- B - Collector, DC powered:
- EM with permanent magnet excitation.
- EM with excitation coil.
UGO transformers and chokes
Examples of graphical symbols for these devices can be found in the figure below.
Correct designation of transformers, inductors and chokes (GOST 2.723-78) Description of designations:
- A - This graphic symbol can be used to designate inductors or transformer windings.
- B - Choke, which has a ferrimagnetic core (magnetic circuit).
- 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 devices and radio components
A brief overview of the UGO data of electronic components is shown below. For those who want to become more familiar with this information, we recommend that you look through GOSTs 2.729 68 and 2.730 73.
Examples of conventional graphic symbols for electronic components and measuring instruments Description of designations:
- Electricity meter.
- Picture of an ammeter.
- Mains voltage measuring device.
- Thermal sensor.
- Constant value resistor.
- Variable resistor.
- Condenser (general designation).
- Electrolytic capacity.
- Diode designation.
- Light-emitting diode.
- Image of a diode optocoupler.
- UGO transistor (in this case, npn).
- Fuse designation.
UGO lighting fixtures
Consider how electric lamps are displayed on a schematic diagram.
Description of designations:
- A - General image of incandescent lamps (LN).
- B - LN as a signaling device.
- C - Type designation of discharge lamps.
- D - Gas-discharge light source of increased pressure (the figure shows an example of a design with two electrodes)
Designation of elements in the wiring diagram
Completing the topic of graphic symbols, we give examples of the display of outlets and switches.
As depicted sockets of other types, it is not difficult to find in the regulatory documents that are available on the network.
This article is intended to give a beginner radio amateur where to start. In various technical publications, such material is also rare. That is why he is valuable.
The table shows the letter designation of the main radio elements on radio circuits in accordance with the state standard (GOST). The letter designation of radio elements indicated in the table is not a dogma, and is generally not followed by the developers of radio circuits. For example, in accordance with GOST, the designation of a potentiometer (variable resistor) is RP, and in the diagrams it is most often found simply - R. When a specialist of any level "reads" a radio circuit, he unmistakably determines that the letter designation refers specifically to this potentiometer, and not to another radio element. The main thing is that the first letter of the designation matches.
There were times when I designed a circuit, and when I put letters on the circuit, I suddenly found that I did not remember which letter was used to designate a rarely used element. Then I turned to this plate. Therefore, this table with letter designations can be useful not only for novice radio amateurs.
| Basic designation | Item name | Additional designation | Device type |
| A | Device | AA AK AKS | Current regulator Relay box Device |
| B | Converters | BA Bf BK BL BM BS | Speaker Telephone Thermal sensor Photocell Microphone Pickup |
| FROM | Capacitors | SV CG | Power capacitor battery Charging capacitor bank |
| D | Integrated circuits, microassemblies | DA DD | Analog IC IC digital, logic element |
| E | Elements are different | EK EL | Heat electric heater Lighting lamp |
| F | Arresters, fuses, protection devices | FA FP FU FV | Discrete instantaneous current protection element Discrete inertial current protection element Fuse fuse Spark gap |
| G | Generators, power supplies | GB GC GE | Battery accumulator Synchronous compensator Generator exciter |
| H | Indicating and signaling devices | HA HG HL HLA HLG HLR HLW HV | Sound alarm device Indicator Light signaling device Signal board Signal lamp with green lens Signal lamp with red lens Signal lamp with white lens Ionic and semiconductor indicators |
| K | Relays, contactors, starters | KA KH KK KM KT KV KCC KCT KL | Relay current Indicator relay Electric thermal relay Contactor, magnetic starter Time relay Voltage relay Close command relay Trip command relay Relay intermediate |
| L | Inductors, chokes | LL LR LM | Fluorescent light choke Reactor Excitation winding of the electric motor |
| M | Engines | MA | Electric motors |
| R | Measuring devices | PA PC PF PI PK PR PT PV PW | Ammeter Pulse counter Frequency counter Active energy meter Reactive energy meter Ohmmeter Action time meter, clock Voltmeter Wattmeter |
| Q | Power switches and disconnectors | QF | Automatic switch |
| R | Resistors | RK RP RS RU RR | Thermistor Potentiometer Measuring shunt Varistor Rheostat |
| S | Control and switching devices | SA SB SF | Switch, or switch Push-button switch Automatic switch |
| T | Transformers, autotransformers | TA TV | Current transformer Voltage transformer |
| U | Converters | UB UR UG UF | Modulator Demodulator Power Supply Frequency converter |
| V | Electrovacuum and semiconductor devices | VD VL VT VS | Diode, Zener diode Electrovacuum device Transistor Thyristor |
| X | Pin connectors | XA XP XS XW | Current collector Pin Nest High frequency connector |
| Y | Mechanical devices with electromagnetic drive | YA YAB | Electromagnet Electromagnetic lock |
FROM where does practical electronics begin? Of course with radio components! Their variety is simply amazing. Here you will find articles about all kinds of radio components, get acquainted with their purpose, parameters and properties. Learn where and in what devices certain electronic components are used.
To go to the article of interest, click on the link or the thumbnail, placed next to the brief description of the material.
How to buy radio parts over the Internet? This question is asked by many radio amateurs. The article describes how you can order radio parts in the online radio parts store with mail delivery.
In this article I will tell you how to buy radio parts and electronic modules in one of the largest online stores AliExpress.com for very little money :)
In addition to the widespread flat SMD resistors in electronics, MELF resistors in a cylindrical case are used. What are their advantages and disadvantages? Where are they used and how to determine their power?
SMD resistor package sizes are standardized, and they are probably known to many. But is it that simple? Here you will learn about two systems for coding the sizes of SMD components, learn how to determine the real size of a chip resistor by its size and vice versa. Get to know the smallest representatives of SMD resistors that exist now. In addition, a table of standard sizes of SMD resistors and their assemblies is presented.
Here you will learn what the temperature coefficient of resistance of a resistor (TCR) is, as well as what TCR different types of fixed resistors have. The formula for calculating the TCS is given, as well as explanations about foreign designations like T.C.R and ppm / 0 С.
In addition to constant resistors, variable and trimming resistors are actively used in electronics. How variable and trimming resistors are arranged, about their varieties, and will be discussed in this article. The material is supported by a large number of photographs of various resistors, which will certainly appeal to novice radio amateurs, who will be able to more easily navigate in all the variety of these elements.
Like any radio component, variables and trimming resistors have basic parameters. It turns out that there are not so few of them, and it will not hurt for novice radio amateurs to get acquainted with such interesting parameters of variable resistors as TCS, functional characteristics, durability, etc.
A semiconductor diode is one of the most popular and widely used components in electronics. What parameters does the diode have? Where is it used? What are its varieties? This will be the topic of this article.
What is an inductor and why is it used in electronics? Here you will learn not only about what parameters the inductor has, but also how the different inductors are indicated on the diagram. The article contains many photographs and images.
In modern pulse technology, a Schottky diode is actively used. How does it differ from conventional rectifier diodes? How is it indicated in the diagrams? What are its positive and negative properties? You will learn about all this in the article about the Schottky diode.
Zener diode is one of the most important elements in modern electronics. It is no secret that semiconductor electronics are very demanding on the quality of power supply, or, more precisely, on the stability of the supply voltage. Here a semiconductor diode comes to the rescue - a zener diode, which is actively used to stabilize the voltage in the nodes of electronic equipment.
What is varicap and where is it used? In this article, you will learn about an amazing diode that is used as a variable capacitor.
If you are into electronics, then you probably faced the task of connecting multiple speakers or speakers. This may be required, for example, when assembling a loudspeaker yourself, connecting several speakers to a single-channel amplifier, and so on. 5 illustrative examples are considered. Lots of photos.
The transistor is the backbone of modern electronics. His invention revolutionized radio engineering and served as the basis for the miniaturization of electronics - the creation of microcircuits. How is the transistor indicated in the circuit diagram? How should the transistor be soldered to the PCB? You will find answers to these questions in this article.
A composite transistor or in another way a Darlington transistor is one of the modifications of a bipolar transistor. You will learn about where composite transistors are used, about their features and distinctive properties from this article.
When selecting analogs of MIS field-effect transistors, one has to refer to the technical documentation with the parameters and characteristics of a particular transistor. In this article, you will learn about the basic parameters of power MOSFET transistors.
Currently, field-effect transistors are increasingly used in electronics. On the schematic diagrams, the field-effect transistor is designated differently. The article describes the conventional graphic designation of field-effect transistors on schematic diagrams.
What is an IGBT transistor? Where is it used and how does it work? In this article, you will learn about the advantages of IGBT transistors, as well as how this type of transistor is indicated on circuit diagrams.
Among the huge number of semiconductor devices, there is a dinistor. You can find out how a dinistor differs from a semiconductor diode by reading this article.
What is a suppressor? Protective diodes or suppressors are increasingly used in electronic equipment to protect it from high-voltage impulse noise. You will learn about the purpose, parameters and methods of using protective diodes from this article.
Self-resetting fuses are increasingly used in electronic equipment. They can be found in security automation devices, computers, portable devices ... In a foreign manner, self-healing fuses are called PTC Resettable Fuses. What are the properties and parameters of the "immortal" fuse? You will learn about this from the proposed article.
Currently, solid-state relays are increasingly used in electronics. What is the advantage of solid state relays over electromagnetic and reed relays? Device, features and types of solid state relays.
In the literature on electronics, the quartz resonator is undeservedly deprived of attention, although this electromechanical component has extremely strongly influenced the active development of radio communication technology, navigation and computing systems.
In addition to the well-known aluminum electrolytic capacitors in electronics, a large number of all kinds of electrolytic capacitors with different types of dielectric are used. Among them, for example, tantalum smd capacitors, non-polar electrolytic and tantalum output capacitors. This article will help novice radio amateurs recognize various electrolytic capacitors among all kinds of radioelements.
Along with other capacitors, electrolytic capacitors have some specific properties that must be considered when used in homemade electronic devices, as well as when repairing electronics.
Designation of radio components in the diagram
This article provides appearance and schematic designation radio parts
Each probably novice radio amateur saw both externally radio components and possibly circuits, but what is on the circuit has to think or search for a long time, and only somewhere he can read and see new words for himself such as resistor, transistor, diode and so on. they are designated. Let us analyze in this article. And so off we go.
1.Resistor
Most often, you can see a resistor on boards and circuits, since there are the most of them on boards.
Resistors can be both constant and variable (you can adjust the resistance with a knob)
One of the pictures of the permanent resistor below and designation permanent and variable on the diagram.
And where does the variable resistor look like? This is still a picture below. I apologize for writing this article.
2.Transistor and its designation
Much information has been written about their functions, but since the topic is about notation, let's talk about notation.
Transistors are bipolar, and polar, PNP and NPN transitions. All this is taken into account when soldering to a board, and in circuits. See the picture, you will understand
Transistor designation npn transition npn
This is emitter, To this collector, and B is baseThe transistors of pnp transitions will differ in that the arrow will not be from the base but to the base. For more details, one more picture
There are also bipolar and field-effect transistors, the designations on the diagram of field-effect transistors are similar, but different, since there is no base of the emitter and collector, but there is C - drain, I - source, Z - gate
And finally, about the transistors, what do they really look like
In general, if the part has three legs, then 80 percent of the fact that it is a transistor.
If you have a transistor and do not know what transition it is and where the collector, base, and all other information is, then look in the transistor reference book.
Capacitor, appearance and designation
Capacitors are polar and non-polar, in polar ones on the circuit they add a plus, since it is for direct current, and non-polar, respectively, for alternating current.
They have a certain capacitance in mKF (microfarads) and are designed for a certain voltage in volts. All this can be read on the capacitor case
Microcircuits, appearance designation on the diagram
Uff dear readers, there are just a huge number of these in the world, starting from amplifiers and ending with TVs
