Radio parts - designations on the diagram. How to read the designations of radio components in the diagram?

In the article you will learn about what radio components exist. Designations on the scheme according to GOST will be considered. You need to start with the most common ones - resistors and capacitors.

To assemble any design, you need to know how the radio components look in reality, as well as how they are indicated on the electrical circuits. There are a lot of radio components - transistors, capacitors, resistors, diodes, etc.

Capacitors

Capacitors are parts that are found in any design without exception. Usually the simplest capacitors are two metal plates. And air acts as a dielectric component. I immediately recall the physics lessons at school when the topic of capacitors was discussed. As a model, two huge flat glands of round shape were used. They were brought closer to each other, then moved away. And in each position, measurements were taken. It is worth noting that instead of air, mica can be used, as well as any material that does not conduct electric current. Designations of radio components on imported circuit diagrams differ from GOSTs adopted in our country.

Please note that direct current does not pass through conventional capacitors. On the other hand, alternating current passes through it without much difficulty. Given this property, a capacitor is installed only where it is necessary to separate the AC component in direct current. Therefore, we can make an equivalent circuit (according to the Kirchhoff theorem):

1. When working on alternating current, the capacitor is replaced by a segment of the conductor with zero resistance.
2. When working in a DC circuit, the capacitor is replaced (no, not by the capacity!) With resistance.

The main characteristic of a capacitor is electric capacitance. The unit of capacity is Farad. She is very big. In practice, as a rule, capacitors are used , the capacitance of which is measured in microfarads, nanofarads, microfarads. In the diagrams, the capacitor is indicated in the form of two parallel bars, from which the bends go.

Variable capacitors

There is also a type of device in which the capacity changes (in this case, due to the fact that there are movable plates). The capacity depends on the size of the plate (in the formula S is its area), as well as on the distance between the electrodes. In a variable capacitor with an air dielectric, for example, due to the presence of a moving part, it is possible to quickly change the area. Consequently, the capacity will also change. But the designation of radio components on foreign circuits is somewhat different. For example, a resistor is depicted on them in the form of a broken curve.

One of the varieties of variable capacitors is tuning. They are actively used in circuits in which there is a strong dependence on stray capacitances. And if you install a capacitor with a constant value, then the whole structure will not work correctly. Therefore, it is necessary to install a universal element, which, after final installation, can be adjusted and fixed in the optimal position. On the diagrams are denoted in the same way as constant, but only parallel plates are crossed out by an arrow.

Fixed capacitors

These elements have differences in design, as well as in the materials from which they are made. The most popular types of dielectrics can be distinguished:

1. Air.
2. Mica.
3. Ceramics.

But this applies exclusively to non-polar elements. There are also electrolytic capacitors (polar). Such elements have very large capacities - starting from tenths of microfarads and ending with several thousand. In addition to capacitance, such elements have another parameter - the maximum voltage value at which its use is allowed. These parameters are written on the circuits and on the capacitor housings.

Capacitor designations in the diagrams

It is worth noting that in the case of using tuning or variable capacitors, two values ​​are indicated - the minimum and maximum capacitance. In fact, on the case you can always find a certain range in which the capacity will change if you turn the axis of the device from one extreme position to another.

Suppose there is a variable capacitor with a capacity of 9-240 (the default measurement in picofarads). This means that with a minimum overlap of the plates, the capacitance will be 9 pF. And at the maximum - 240 pF. It is worth considering in more detail the designation of radio components on the diagram and their name in order to be able to read technical documentation correctly.

Capacitor connection

Immediately, three types can be distinguished (there are just so many) compounds of elements:

1. Sequential - the total capacity of the entire chain is easy to calculate. In this case, it will be equal to the product of all capacities of elements divided by their sum.
2. Parallel - in this case, calculating the total capacity is even easier. It is necessary to add the capacitance of all the capacitors included in the chain.
3. Mixed - in this case, the scheme is divided into several parts. We can say that it is simplified - one part only contains elements connected in parallel, the second part only in series.

And this is only general information about capacitors, in fact, a lot of them can be talked about, interesting examples can be cited.

Resistors: general

These elements can also be found in any design - at least in the radio, at least in the control circuit on the microcontroller. This is a porcelain tube on which a thin film of metal (carbon - in particular, soot) is sprayed from the outside. However, even graphite can be applied - the effect will be similar. If the resistors have a very low resistance and high power, then a nichrome wire is used as a conductive layer .

The main characteristic of a resistor is resistance. Used in electrical circuits to set the required current value in certain circuits. At physics lessons, a comparison was made with a barrel filled with water: if you change the diameter of the pipe, you can adjust the speed of the stream. It should be noted that resistance depends on the thickness of the conductive layer. The thinner this layer, the higher the resistance. In this case, the symbols of the radio components in the diagrams do not depend on the size of the element.

Fixed resistors

As for such elements, the most common types can be distinguished:

1. Metallized varnished heat-resistant - abbreviated as MLT.
2. Moisture resistant resistance - BC.
3. Small varnished carbonaceous - ULM.

Resistors have two main parameters - power and resistance. The last parameter is measured in ohms. But this unit of measurement is extremely small, therefore, in practice, you will often find elements in which resistance is measured in megaohms and kilograms. Power is measured exclusively in watts. Moreover, the dimensions of the element depend on the power. The larger it is, the larger the element. And now about the designation of radio components. On the diagrams of imported and domestic devices, all elements can be designated differently.

In domestic circuits, a resistor is a small rectangle with an aspect ratio of 1: 3, its parameters are written either on the side (if the element is located vertically) or on top (in the case of horizontal arrangement). First, the Latin letter R is indicated, then the serial number of the resistor in the circuit.

Variable resistor (potentiometer)

Constant resistances have only two conclusions. But the variables are three. On electrical circuits and on the housing of the element, the resistance between the two extreme contacts is indicated. But between the middle and any of the extreme resistance will vary depending on what position the axis of the resistor is in. In this case, if you connect two ohmmeters, you can see how the reading of one will change in a smaller direction, and the second - in a larger one. You need to understand how to read the circuits of electronic devices. The designation of radio components is also not superfluous to know.

The total resistance (between the extreme terminals) will remain unchanged. Variable resistors are used to control the gain (with their help you change the volume in radios, televisions). In addition, variable resistors are actively used in automobiles. These are fuel level sensors, speed controllers for electric motors, and lighting brightness.

Resistor connection

In this case, the picture is completely opposite to that of the capacitors:

1. Serial connection - the resistance of all elements in the circuit is added.
2. Parallel connection - the product of resistances is divided by the sum.
3. Mixed - the whole scheme is divided into smaller chains and is calculated in stages.

With this, you can close the overview of resistors and begin to describe the most interesting elements - semiconductor (designation of radio components on the circuits, GOST for UGO, discussed below).

Semiconductors

This is the largest part of all radio elements, since semiconductors include not only zener diodes, transistors, diodes, but also varicaps, variconds, thyristors, triacs, microcircuits, etc. Yes, microcircuits are one crystal on which there can be a great many radio elements - and capacitors, and resistances, and pn junctions.

As you know, there are conductors (metals, for example), dielectrics (wood, plastic, fabrics). The designations of radio components on the circuit may be different (a triangle is most likely a diode or a zener diode). But it is worth noting that a triangle without additional elements indicates logical ground in microprocessor technology.

These materials either conduct current or not, regardless of the state of aggregation. But there are semiconductors, whose properties vary depending on specific conditions. These are materials such as silicon, germanium. By the way, glass can also be partially attributed to semiconductors - in the normal state it does not conduct current, but when heated, the picture is completely opposite.

Diodes and Zener Diodes

A semiconductor diode has only two electrodes: a cathode (negative) and an anode (positive). But what are the features of this radio component? Designations in the diagram can see above. So, you connect the power source with a plus to the anode and a minus to the cathode. In this case, an electric current will flow from one electrode to another. It should be noted that in this case the element has an extremely low resistance. Now you can conduct an experiment and connect the battery on the contrary, then the current resistance increases several times, and it stops going. And if you direct an alternating current through the diode, you will get a constant output (though with small ripples). When using a bridge switching circuit, two half-waves (positive) are obtained.

Zener diodes, like diodes, have two electrodes - a cathode and an anode. In direct connection, this element works in exactly the same way as the diode considered above. But if you put the current in the opposite direction, you can see a very interesting picture. Initially, the zener diode does not pass current through itself. But when the voltage reaches a certain value, a breakdown occurs, and the element conducts a current. This is the voltage stabilization. A very good property, thanks to which it is possible to achieve a stable voltage in the circuits, completely get rid of vibrations, even the smallest. The designation of the radio parts on the diagrams is in the form of a triangle, and at its top there is a line perpendicular to the height.

Transistors

If diodes and zener diodes can sometimes not even be found in designs, then you will find transistors in any (except for the detector receiver). Transistors have three electrodes:

1. Base (abbreviated by the letter "B" is indicated).
2. Collector (K).
3. Emitter (E).

Transistors can work in several modes, but most often they are used in the amplifier and key (like a switch). You can make a comparison with a speaker - they shouted at the base, an amplified voice flew out of the collector. And hold on to the emitter - this is the case. The main characteristic of transistors is the gain (ratio of collector current to base). It is this parameter, along with many others, that is fundamental to this radio component. The designations on the circuit of the transistor are a vertical line and two lines approaching it at an angle. There are several most common types of transistors:

1. Polar.
2. Bipolar.
3. Field

There are also transistor assemblies consisting of several amplifying elements. These are the most common radio components. The notation in the diagram was considered in the article.