When assembling homemade electronic circuits, you are inevitably faced with the selection of the necessary capacitors.

Moreover, to assemble the device, you can use capacitors that have already been used and have worked for some time in electronic equipment.

Naturally, before reuse, it is necessary to check capacitors, especially electrolytic ones, which are more susceptible to aging.

When selecting capacitors of constant capacity, it is necessary to understand the markings of these radio elements, otherwise, if there is an error, the assembled device will either refuse to work correctly or will not work at all. The question arises, how to read the capacitor markings?

A capacitor has several important parameters that should be taken into account when using them.

The first thing is rated capacitance. It is measured in fractions of Farad.

The second is permission. Or in another way permissible deviation of nominal capacity from the specified one. This parameter is rarely taken into account, since household radio equipment uses radio elements with a tolerance of up to ±20%, and sometimes more. It all depends on the purpose of the device and the features of a particular device. This parameter is usually not indicated on circuit diagrams.

The third thing indicated in the labeling is permissible operating voltage. This is a very important parameter and you should pay attention to it if the capacitor will be used in high-voltage circuits.

So, let's figure out how capacitors are marked.

Some of the most popular capacitors that can be used are constant capacitors K73 - 17, K73 - 44, K78 - 2, ceramic KM-5, KM-6 and the like. Analogues of these capacitors are also used in imported electronic equipment. Their labeling differs from domestic ones.

Domestic-made capacitors K73-17 are polyethylene terephthalate film protected capacitors. The housing of these capacitors is marked with an alphanumeric index, for example 100nJ, 330nK, 220nM, 39nJ, 2n2M.

K73 series capacitors and their markings

Labeling rules.

Capacitances from 100 pF to 0.1 µF are marked in nanofarads, indicating the letter H or n.

Designation 100 n is the value of the nominal capacity. For 100n - 100 nanofarads (nF) - 0.1 microfarads (uF). Thus, a capacitor with index 100n has a capacity of 0.1 μF. Similar for other notations. Eg:
330n – 0.33 µF, 10n – 0.01 µF. For 2n2 – 0.0022 µF or 2200 picofarads (2200 pF).

You can find markings like 47 H C. This entry corresponds to 47 n K and is 47 nanofarads or 0.047 µF. Similar to 22NS - 0.022 µF.

In order to easily determine the capacity, you need to know the designations of the main submultiple units - milli, micro, nano, pico and their numerical values. Read more about this.

Also in the marking of K73 capacitors there are such designations as M47C, M10C.
Here, letter M conventionally means microfarad. The value 47 comes after M, i.e. the nominal capacitance is a fraction of a microfarad, i.e. 0.47 µF. For M10C - 0.1 µF. It turns out that capacitors marked M10C and 100nJ have the same capacity. The only differences are in the recording.

Thus, capacitance from 0.1 µF and above is indicated with the letter M, m Instead of a decimal point, the leading zero is omitted.

The nominal capacity of domestic capacitors up to 100 pF is indicated in picofarads, putting the letter P or p after the number. If the capacitance is less than 10 pF, then put the letter R and two numbers. For example, 1R5 = 1.5 pF.

On ceramic capacitors (type KM5, KM6), which are small in size, usually only a numerical code is indicated. Here, look at the photo.

Ceramic capacitors with capacitance marked with a numerical code

For example, numerical marking 224 corresponds to value 22 0000 picofarad, or 220 nanofarad and 0.22 µF. In this case, 22 is the numerical value of the denomination value. The number 4 indicates the number of zeros. The result the number is the capacitance value in picofarads. Writing 221 means 220 pF, and writing 220 means 22 pF. If the marking uses a four-digit code, then the first three digits are the numerical value of the denomination value, and the last, fourth, is the number of zeros. So at 4722, the capacitance is 47200 pF - 47.2 nF. I think we've sorted this out.

The permissible deviation of the capacity is marked either with a percentage number (±5%, 10%, 20%) or with a Latin letter. Sometimes you can find the old tolerance designation encoded with a Russian letter. The permissible deviation of capacitance is similar to the tolerance for the resistance value of resistors.

Letter code of capacity deviation (tolerance).

So, if a capacitor with the following marking is M47C, then its capacity is 0.047 μF, and the tolerance is ±10% (according to the old marking with a Russian letter). It is quite difficult to find a capacitor with a tolerance of ±0.25% (as marked with a Latin letter) in household equipment, which is why a value with a larger error was chosen. Mainly, capacitors with approval are widely used in household equipment. H, M, J, K. The letter indicating the tolerance is indicated after the value of the nominal capacity, like this 22n K, 220n M, 470n J.

Table for deciphering the conditional letter code of the permissible deviation of the capacity.

Marking of capacitors by operating voltage.

An important parameter of the capacitor is also the permissible operating voltage. It should be taken into account when assembling homemade electronics and repairing household radio equipment. For example, when repairing compact fluorescent lamps, it is necessary to select a capacitor for the appropriate voltage when replacing failed ones. It would be a good idea to take a capacitor with a margin of operating voltage.

Typically, the value of the permissible operating voltage is indicated after the rated capacity and tolerance. It is designated in volts with the letter B (old marking) and V (new). For example, like this: 250V, 400V, 1600V, 200V. In some cases, the V is omitted.

Sometimes Latin letter coding is used. To decipher, you should use the table of letter coding of the operating voltage.

Thus, we learned how to determine the capacitance of a capacitor by marking, and along the way we became acquainted with its main parameters.

The marking of imported capacitors is different, but largely corresponds to what is described.

The material is an explanation and addition to the article:
Units of measurement of physical quantities in radio electronics
Units of measurement and relationships of physical quantities used in radio engineering.

If particles charged in a certain way (for example, electrons) are removed from one body to another, then due to the excess of charged particles, a potential difference, that is, an electric voltage, will arise between the two bodies. The capacitance between two bodies tells us how many charged particles need to be transferred from one body to another in order to obtain a given voltage.

Length and distance converter Mass converter Converter of volume measures of bulk products and food products Area converter Converter of volume and units of measurement in culinary recipes Temperature converter Converter of pressure, mechanical stress, Young's modulus Converter of energy and work Converter of power Converter of force Converter of time Linear speed converter Flat angle Converter thermal efficiency and fuel efficiency Converter of numbers in various number systems Converter of units of measurement of quantity of information Currency rates Women's clothing and shoe sizes Men's clothing and shoe sizes Angular velocity and rotation frequency converter Acceleration converter Angular acceleration converter Density converter Specific volume converter Moment of inertia converter Moment of force converter Torque converter Specific heat of combustion converter (by mass) Energy density and specific heat of combustion converter (by volume) Temperature difference converter Coefficient of thermal expansion converter Thermal resistance converter Thermal conductivity converter Specific heat capacity converter Energy exposure and thermal radiation power converter Heat flux density converter Heat transfer coefficient converter Volume flow rate converter Mass flow rate converter Molar flow rate converter Mass flow density converter Molar concentration converter Mass concentration in solution converter Dynamic (absolute) viscosity converter Kinematic viscosity converter Surface tension converter Vapor permeability converter Water vapor flow density converter Sound level converter Microphone sensitivity converter Converter Sound Pressure Level (SPL) Sound Pressure Level Converter with Selectable Reference Pressure Luminance Converter Luminous Intensity Converter Illuminance Converter Computer Graphics Resolution Converter Frequency and Wavelength Converter Diopter Power and Focal Length Diopter Power and Lens Magnification (×) Converter electric charge Linear charge density converter Surface charge density converter Volume charge density converter Electric current converter Linear current density converter Surface current density converter Electric field strength converter Electrostatic potential and voltage converter Electrical resistance converter Electrical resistivity converter Electrical conductivity converter Electrical conductivity converter Electrical capacitance Inductance Converter American Wire Gauge Converter Levels in dBm (dBm or dBm), dBV (dBV), watts, etc. units Magnetomotive force converter Magnetic field strength converter Magnetic flux converter Magnetic induction converter Radiation. Ionizing radiation absorbed dose rate converter Radioactivity. Radioactive decay converter Radiation. Exposure dose converter Radiation. Absorbed dose converter Decimal prefix converter Data transfer Typography and image processing unit converter Timber volume unit converter Calculation of molar mass Periodic table of chemical elements by D. I. Mendeleev

1 farad [F] = 1000000 microfarad [µF]

Initial value

Converted value

farad exafarad petafarad terafarad gigafarad megafarad kilofarad hectofarad decafarad decifarad centifarad millifarad microfarad nanofarad picofarad femtofarad attofarad coulomb per volt abfarad unit of capacitance SGSM statfarad unit of capacitance SGSE

Linear charge density

More about electrical capacitance

General information

Electric capacitance is a quantity characterizing the ability of a conductor to accumulate charge, equal to the ratio of the electric charge to the potential difference between the conductors:

C = Q/∆φ

Here Q- electric charge, measured in coulombs (C), - potential difference, measured in volts (V).

In the SI system, electrical capacitance is measured in farads (F). This unit of measurement is named after the English physicist Michael Faraday.

A farad is a very large capacitance for an insulated conductor. Thus, a solitary metal ball with a radius of 13 solar radii would have a capacity equal to 1 farad. And the capacitance of a metal ball the size of Earth would be approximately 710 microfarads (µF).

Since 1 farad is a very large capacitance, smaller values ​​are used, such as: microfarad (μF), equal to one millionth of a farad; nanofarad (nF), equal to one billionth; picofarad (pF), equal to one trillionth of a farad.

In the SGSE system, the basic unit of capacity is the centimeter (cm). 1 centimeter of capacity is the electrical capacity of a ball with a radius of 1 centimeter placed in a vacuum. GSSE is an extended GSSE system for electrodynamics, that is, a system of units in which the centimeter, gram, and second are taken as the basic units for calculating length, mass and time, respectively. In extended GHS, including SGSE, some physical constants are taken to be unity to simplify formulas and facilitate calculations.

Capacity Usage

Capacitors - devices for storing charge in electronic equipment

The concept of electrical capacitance refers not only to a conductor, but also to a capacitor. A capacitor is a system of two conductors separated by a dielectric or vacuum. In its simplest form, the capacitor design consists of two electrodes in the form of plates (plates). A capacitor (from Latin condensare - “to compact”, “to thicken”) is a two-electrode device for accumulating charge and energy of an electromagnetic field; in the simplest case, it consists of two conductors separated by some kind of insulator. For example, sometimes radio amateurs, in the absence of ready-made parts, make tuning capacitors for their circuits from pieces of wire of different diameters, insulated with a varnish coating, with a thinner wire wound around a thicker one. By adjusting the number of turns, radio amateurs precisely tune the equipment circuit to the desired frequency. Examples of images of capacitors on electrical circuits are shown in the figure.

Historical reference

Even 275 years ago, the principles of creating capacitors were known. Thus, in 1745 in Leiden, the German physicist Ewald Jürgen von Kleist and the Dutch physicist Pieter van Musschenbroek created the first capacitor - the “Leyden jar” - in which the dielectric was the walls of a glass jar, and the plates were the water in the vessel and the experimenter’s palm holding the vessel. Such a “can” made it possible to accumulate a charge on the order of a microcoulomb (µC). After it was invented, it was often experimented with and performed in public. To do this, the jar was first charged with static electricity by rubbing it. After this, one of the participants touched the can with his hand and received a small electric shock. It is known that 700 Parisian monks held hands and conducted the Leiden experiment. The moment the first monk touched the head of the jar, all 700 monks, overcome by one convulsion, screamed in horror.

The “Leyden jar” came to Russia thanks to the Russian Tsar Peter I, who met Muschenbruck while traveling in Europe, and learned more about the experiments with the “Leyden jar”. Peter I established the Academy of Sciences in Russia, and ordered Muschenbruck various instruments for the Academy of Sciences.

Subsequently, capacitors were improved and became smaller, and their capacity became larger. Capacitors are widely used in electronics. For example, a capacitor and inductor form an oscillating circuit that can be used to tune a receiver to the desired frequency.

There are several types of capacitors, differing in constant or variable capacitance and dielectric material.

Examples of capacitors

The industry produces a large number of types of capacitors for various purposes, but their main characteristics are capacity and operating voltage.

Typical value containers capacitors vary from units of picofarads to hundreds of microfarads, with the exception of ionistors, which have a slightly different nature of capacitance formation - due to the double layer of the electrodes - in this they are similar to electrochemical batteries. Nanotube-based supercapacitors have extremely developed electrode surfaces. These types of capacitors have typical capacitance values ​​in the tens of farads, and in some cases they can replace traditional electrochemical batteries as current sources.

The second most important parameter of capacitors is its operating voltage. Exceeding this parameter can lead to failure of the capacitor, therefore, when constructing real circuits, it is customary to use capacitors with double the operating voltage.

To increase the capacitance values ​​or operating voltage, the technique of combining capacitors into batteries is used. When two capacitors of the same type are connected in series, the operating voltage doubles and the total capacitance is halved. When two capacitors of the same type are connected in parallel, the operating voltage remains the same, but the total capacitance doubles.

The third most important parameter of capacitors is temperature coefficient of change of capacitance (TKE). It gives an idea of ​​the change in capacity under changing temperatures.

Depending on the purpose of use, capacitors are divided into general-purpose capacitors, the requirements for the parameters of which are not critical, and into special-purpose capacitors (high-voltage, precision and with various TKE).

Capacitor markings

Like resistors, depending on the dimensions of the product, full markings may be used indicating the rated capacity, class of deviation from the rated value and operating voltage. For small-sized versions of capacitors, code markings of three or four digits, mixed alphanumeric markings and color markings are used.

The corresponding tables for converting markings by rating, operating voltage and TKE can be found on the Internet, but the most effective and practical method of checking the rating and serviceability of an element of a real circuit remains the direct measurement of the parameters of a soldered capacitor using a multimeter.

Warning: Since capacitors can accumulate a large charge at very high voltages, to avoid electric shock, it is necessary to discharge the capacitor before measuring its parameters by shorting its terminals with a wire with high external insulation resistance. The standard meter leads are best suited for this.

Oxide capacitors: This type of capacitor has a large specific capacitance, that is, capacitance per unit weight of the capacitor. One plate of such capacitors is usually an aluminum strip coated with a layer of aluminum oxide. The second plate is the electrolyte. Since oxide capacitors have polarity, it is fundamentally important to include such a capacitor in the circuit strictly in accordance with the polarity of the voltage.

Solid capacitors: Instead of a traditional electrolyte, they use an organic polymer that conducts current, or a semiconductor, as the plating.

Variable capacitors: Capacitance can be changed mechanically, electrically, or by temperature.

Film capacitors: The capacitance range of this type of capacitor is approximately 5 pF to 100 µF.

There are other types of capacitors.

Ionistors

These days, ionistors are gaining popularity. An ionistor (supercapacitor) is a hybrid of a capacitor and a chemical current source, the charge of which accumulates at the interface between two media - the electrode and the electrolyte. The creation of ionistors began in 1957, when a capacitor with a double electrical layer on porous carbon electrodes was patented. The double layer, as well as the porous material, helped increase the capacitance of such a capacitor by increasing the surface area. Subsequently, this technology was supplemented and improved. Ionistors entered the market in the early eighties of the last century.

With the advent of ionistors, it became possible to use them in electrical circuits as voltage sources. Such supercapacitors have a long service life, low weight, and high charging and discharging rates. In the future, this type of capacitors can replace conventional batteries. The main disadvantages of ionistors are lower specific energy (energy per unit weight) than electrochemical batteries, low operating voltage and significant self-discharge.

Ionistors are used in Formula 1 cars. In energy recovery systems, braking generates electricity that is stored in the flywheel, batteries or supercapacitors for later use. A2B electric vehicle from the University of Toronto. Under the hood

Electric cars are currently produced by many companies, for example: General Motors, Nissan, Tesla Motors, Toronto Electric. The University of Toronto has teamed up with Toronto Electric to develop the all-Canadian A2B electric vehicle. It uses supercapacitors together with chemical power supplies, so-called hybrid electric energy storage. The engines of this car are powered by batteries weighing 380 kilograms. Solar panels installed on the roof of the electric vehicle are also used for recharging.

Capacitive touch screens

Modern devices increasingly use touch screens, which allow you to control devices by touching indicator panels or screens. Touch screens come in different types: resistive, capacitive and others. They can respond to one or more simultaneous touches. The operating principle of capacitive screens is based on the fact that a large capacitance object conducts alternating current. In this case, this object is the human body.

Surface capacitive screens

Thus, a surface capacitive touch screen is a glass panel coated with a transparent resistive material. An alloy of indium oxide and tin oxide, which has high transparency and low surface resistance, is usually used as a resistive material. Electrodes that supply a small alternating voltage to the conductive layer are located at the corners of the screen. When you touch such a screen with your finger, a current leak appears, which is detected in the four corners by sensors and transmitted to the controller, which determines the coordinates of the touch point.

The advantage of such screens is their durability (about 6.5 years of clicks with an interval of one second or about 200 million clicks). They have high transparency (approximately 90%). Thanks to these advantages, capacitive screens have been actively replacing resistive screens since 2009.

The disadvantage of capacitive screens is that they do not work well at low temperatures; there are difficulties in using such screens with gloves. If the conductive coating is located on the outer surface, then the screen is quite vulnerable, so capacitive screens are used only in those devices that are protected from the elements.

Projected capacitive screens

In addition to surface capacitive screens, there are projection capacitive screens. Their difference is that a grid of electrodes is applied on the inside of the screen. The electrode that is touched forms a capacitor together with the human body. Thanks to the grid, you can get precise touch coordinates. The projected capacitive screen responds to touches when wearing thin gloves.

Projected capacitive screens also have high transparency (about 90%). They are durable and quite strong, so they are widely used not only in personal electronics, but also in automatic machines, including those installed on the street.

Do you find it difficult to translate units of measurement from one language to another? Colleagues are ready to help you. Post a question in TCTerms and within a few minutes you will receive an answer.

Length and distance converter Mass converter Converter of volume measures of bulk products and food products Area converter Converter of volume and units of measurement in culinary recipes Temperature converter Converter of pressure, mechanical stress, Young's modulus Converter of energy and work Converter of power Converter of force Converter of time Linear speed converter Flat angle Converter thermal efficiency and fuel efficiency Converter of numbers in various number systems Converter of units of measurement of quantity of information Currency rates Women's clothing and shoe sizes Men's clothing and shoe sizes Angular velocity and rotation frequency converter Acceleration converter Angular acceleration converter Density converter Specific volume converter Moment of inertia converter Moment of force converter Torque converter Specific heat of combustion converter (by mass) Energy density and specific heat of combustion converter (by volume) Temperature difference converter Coefficient of thermal expansion converter Thermal resistance converter Thermal conductivity converter Specific heat capacity converter Energy exposure and thermal radiation power converter Heat flux density converter Heat transfer coefficient converter Volume flow rate converter Mass flow rate converter Molar flow rate converter Mass flow density converter Molar concentration converter Mass concentration in solution converter Dynamic (absolute) viscosity converter Kinematic viscosity converter Surface tension converter Vapor permeability converter Water vapor flow density converter Sound level converter Microphone sensitivity converter Converter Sound Pressure Level (SPL) Sound Pressure Level Converter with Selectable Reference Pressure Luminance Converter Luminous Intensity Converter Illuminance Converter Computer Graphics Resolution Converter Frequency and Wavelength Converter Diopter Power and Focal Length Diopter Power and Lens Magnification (×) Converter electric charge Linear charge density converter Surface charge density converter Volume charge density converter Electric current converter Linear current density converter Surface current density converter Electric field strength converter Electrostatic potential and voltage converter Electrical resistance converter Electrical resistivity converter Electrical conductivity converter Electrical conductivity converter Electrical capacitance Inductance Converter American Wire Gauge Converter Levels in dBm (dBm or dBm), dBV (dBV), watts, etc. units Magnetomotive force converter Magnetic field strength converter Magnetic flux converter Magnetic induction converter Radiation. Ionizing radiation absorbed dose rate converter Radioactivity. Radioactive decay converter Radiation. Exposure dose converter Radiation. Absorbed dose converter Decimal prefix converter Data transfer Typography and image processing unit converter Timber volume unit converter Calculation of molar mass Periodic table of chemical elements by D. I. Mendeleev

1 microfarad [uF] = 1E-06 farad [F]

Initial value

Converted value

farad exafarad petafarad terafarad gigafarad megafarad kilofarad hectofarad decafarad decifarad centifarad millifarad microfarad nanofarad picofarad femtofarad attofarad coulomb per volt abfarad unit of capacitance SGSM statfarad unit of capacitance SGSE

More about electrical capacitance

General information

Electric capacitance is a quantity characterizing the ability of a conductor to accumulate charge, equal to the ratio of the electric charge to the potential difference between the conductors:

C = Q/∆φ

Here Q- electric charge, measured in coulombs (C), - potential difference, measured in volts (V).

In the SI system, electrical capacitance is measured in farads (F). This unit of measurement is named after the English physicist Michael Faraday.

A farad is a very large capacitance for an insulated conductor. Thus, a solitary metal ball with a radius of 13 solar radii would have a capacity equal to 1 farad. And the capacitance of a metal ball the size of Earth would be approximately 710 microfarads (µF).

Since 1 farad is a very large capacitance, smaller values ​​are used, such as: microfarad (μF), equal to one millionth of a farad; nanofarad (nF), equal to one billionth; picofarad (pF), equal to one trillionth of a farad.

In the SGSE system, the basic unit of capacity is the centimeter (cm). 1 centimeter of capacity is the electrical capacity of a ball with a radius of 1 centimeter placed in a vacuum. GSSE is an extended GSSE system for electrodynamics, that is, a system of units in which the centimeter, gram, and second are taken as the basic units for calculating length, mass and time, respectively. In extended GHS, including SGSE, some physical constants are taken to be unity to simplify formulas and facilitate calculations.

Capacity Usage

Capacitors - devices for storing charge in electronic equipment

The concept of electrical capacitance refers not only to a conductor, but also to a capacitor. A capacitor is a system of two conductors separated by a dielectric or vacuum. In its simplest form, the capacitor design consists of two electrodes in the form of plates (plates). A capacitor (from Latin condensare - “to compact”, “to thicken”) is a two-electrode device for accumulating charge and energy of an electromagnetic field; in the simplest case, it consists of two conductors separated by some kind of insulator. For example, sometimes radio amateurs, in the absence of ready-made parts, make tuning capacitors for their circuits from pieces of wire of different diameters, insulated with a varnish coating, with a thinner wire wound around a thicker one. By adjusting the number of turns, radio amateurs precisely tune the equipment circuit to the desired frequency. Examples of images of capacitors on electrical circuits are shown in the figure.

Historical reference

Even 275 years ago, the principles of creating capacitors were known. Thus, in 1745 in Leiden, the German physicist Ewald Jürgen von Kleist and the Dutch physicist Pieter van Musschenbroek created the first capacitor - the “Leyden jar” - in which the dielectric was the walls of a glass jar, and the plates were the water in the vessel and the experimenter’s palm holding the vessel. Such a “can” made it possible to accumulate a charge on the order of a microcoulomb (µC). After it was invented, it was often experimented with and performed in public. To do this, the jar was first charged with static electricity by rubbing it. After this, one of the participants touched the can with his hand and received a small electric shock. It is known that 700 Parisian monks held hands and conducted the Leiden experiment. The moment the first monk touched the head of the jar, all 700 monks, overcome by one convulsion, screamed in horror.

The “Leyden jar” came to Russia thanks to the Russian Tsar Peter I, who met Muschenbruck while traveling in Europe, and learned more about the experiments with the “Leyden jar”. Peter I established the Academy of Sciences in Russia, and ordered Muschenbruck various instruments for the Academy of Sciences.

Subsequently, capacitors were improved and became smaller, and their capacity became larger. Capacitors are widely used in electronics. For example, a capacitor and inductor form an oscillating circuit that can be used to tune a receiver to the desired frequency.

There are several types of capacitors, differing in constant or variable capacitance and dielectric material.

Examples of capacitors

The industry produces a large number of types of capacitors for various purposes, but their main characteristics are capacity and operating voltage.

Typical value containers capacitors vary from units of picofarads to hundreds of microfarads, with the exception of ionistors, which have a slightly different nature of capacitance formation - due to the double layer of the electrodes - in this they are similar to electrochemical batteries. Nanotube-based supercapacitors have extremely developed electrode surfaces. These types of capacitors have typical capacitance values ​​in the tens of farads, and in some cases they can replace traditional electrochemical batteries as current sources.

The second most important parameter of capacitors is its operating voltage. Exceeding this parameter can lead to failure of the capacitor, therefore, when constructing real circuits, it is customary to use capacitors with double the operating voltage.

To increase the capacitance values ​​or operating voltage, the technique of combining capacitors into batteries is used. When two capacitors of the same type are connected in series, the operating voltage doubles and the total capacitance is halved. When two capacitors of the same type are connected in parallel, the operating voltage remains the same, but the total capacitance doubles.

The third most important parameter of capacitors is temperature coefficient of change of capacitance (TKE). It gives an idea of ​​the change in capacity under changing temperatures.

Depending on the purpose of use, capacitors are divided into general-purpose capacitors, the requirements for the parameters of which are not critical, and into special-purpose capacitors (high-voltage, precision and with various TKE).

Capacitor markings

Like resistors, depending on the dimensions of the product, full markings may be used indicating the rated capacity, class of deviation from the rated value and operating voltage. For small-sized versions of capacitors, code markings of three or four digits, mixed alphanumeric markings and color markings are used.

The corresponding tables for converting markings by rating, operating voltage and TKE can be found on the Internet, but the most effective and practical method of checking the rating and serviceability of an element of a real circuit remains the direct measurement of the parameters of a soldered capacitor using a multimeter.

Warning: Since capacitors can accumulate a large charge at very high voltages, to avoid electric shock, it is necessary to discharge the capacitor before measuring its parameters by shorting its terminals with a wire with high external insulation resistance. The standard meter leads are best suited for this.

Oxide capacitors: This type of capacitor has a large specific capacitance, that is, capacitance per unit weight of the capacitor. One plate of such capacitors is usually an aluminum strip coated with a layer of aluminum oxide. The second plate is the electrolyte. Since oxide capacitors have polarity, it is fundamentally important to include such a capacitor in the circuit strictly in accordance with the polarity of the voltage.

Solid capacitors: Instead of a traditional electrolyte, they use an organic polymer that conducts current, or a semiconductor, as the plating.

Variable capacitors: Capacitance can be changed mechanically, electrically, or by temperature.

Film capacitors: The capacitance range of this type of capacitor is approximately 5 pF to 100 µF.

There are other types of capacitors.

Ionistors

These days, ionistors are gaining popularity. An ionistor (supercapacitor) is a hybrid of a capacitor and a chemical current source, the charge of which accumulates at the interface between two media - the electrode and the electrolyte. The creation of ionistors began in 1957, when a capacitor with a double electrical layer on porous carbon electrodes was patented. The double layer, as well as the porous material, helped increase the capacitance of such a capacitor by increasing the surface area. Subsequently, this technology was supplemented and improved. Ionistors entered the market in the early eighties of the last century.

With the advent of ionistors, it became possible to use them in electrical circuits as voltage sources. Such supercapacitors have a long service life, low weight, and high charging and discharging rates. In the future, this type of capacitors can replace conventional batteries. The main disadvantages of ionistors are lower specific energy (energy per unit weight) than electrochemical batteries, low operating voltage and significant self-discharge.

Ionistors are used in Formula 1 cars. In energy recovery systems, braking generates electricity that is stored in the flywheel, batteries or supercapacitors for later use. A2B electric vehicle from the University of Toronto. Under the hood

Electric cars are currently produced by many companies, for example: General Motors, Nissan, Tesla Motors, Toronto Electric. The University of Toronto has teamed up with Toronto Electric to develop the all-Canadian A2B electric vehicle. It uses supercapacitors together with chemical power supplies, so-called hybrid electric energy storage. The engines of this car are powered by batteries weighing 380 kilograms. Solar panels installed on the roof of the electric vehicle are also used for recharging.

Capacitive touch screens

Modern devices increasingly use touch screens, which allow you to control devices by touching indicator panels or screens. Touch screens come in different types: resistive, capacitive and others. They can respond to one or more simultaneous touches. The operating principle of capacitive screens is based on the fact that a large capacitance object conducts alternating current. In this case, this object is the human body.

Surface capacitive screens

Thus, a surface capacitive touch screen is a glass panel coated with a transparent resistive material. An alloy of indium oxide and tin oxide, which has high transparency and low surface resistance, is usually used as a resistive material. Electrodes that supply a small alternating voltage to the conductive layer are located at the corners of the screen. When you touch such a screen with your finger, a current leak appears, which is detected in the four corners by sensors and transmitted to the controller, which determines the coordinates of the touch point.

The advantage of such screens is their durability (about 6.5 years of clicks with an interval of one second or about 200 million clicks). They have high transparency (approximately 90%). Thanks to these advantages, capacitive screens have been actively replacing resistive screens since 2009.

The disadvantage of capacitive screens is that they do not work well at low temperatures; there are difficulties in using such screens with gloves. If the conductive coating is located on the outer surface, then the screen is quite vulnerable, so capacitive screens are used only in those devices that are protected from the elements.

Projected capacitive screens

In addition to surface capacitive screens, there are projection capacitive screens. Their difference is that a grid of electrodes is applied on the inside of the screen. The electrode that is touched forms a capacitor together with the human body. Thanks to the grid, you can get precise touch coordinates. The projected capacitive screen responds to touches when wearing thin gloves.

Projected capacitive screens also have high transparency (about 90%). They are durable and quite strong, so they are widely used not only in personal electronics, but also in automatic machines, including those installed on the street.

Do you find it difficult to translate units of measurement from one language to another? Colleagues are ready to help you. Post a question in TCTerms and within a few minutes you will receive an answer.

Convert farad to microfarad:

1. Select the desired category from the list, in this case “Capacity”.
2. Enter the value to be converted. Basic arithmetic operations such as addition (+), subtraction (-), multiplication (*, x), division (/, :, ÷), exponent (^), parentheses and pi (pi) are already supported at this time .
3. From the list, select the unit of measurement of the value being converted, in this case “farad [F]”.
4. Finally, select the unit you want the value to be converted to, in this case "microfarad [µF]".
5. After displaying the result of an operation, and whenever appropriate, an option appears to round the result to a certain number of decimal places.

With this calculator, you can enter the value to be converted along with the original measurement unit, for example, "537 farad". In this case, you can use either the full name of the unit of measurement or its abbreviation, for example, “farad” or “F”. After entering the unit of measurement you want to convert, the calculator determines its category, in this case "Capacity". It then converts the entered value into all the appropriate units of measurement that it knows. In the list of results you will undoubtedly find the converted value you need. Alternatively, the value to be converted can be entered as follows: "28 farad to microfarad", "47 F -> µF" or "56 F = µF". In this case, the calculator will also immediately understand into which unit of measurement the original value needs to be converted. Regardless of which of these options is used, the hassle of searching through long selection lists with countless categories and countless units of measurement is eliminated. All this is done for us by a calculator that copes with its task in a split second.

In addition, the calculator allows you to use mathematical formulas. As a result, not only numbers such as "(96 * 13) F" are taken into account. You can even use multiple units of measurement directly in the conversion field. For example, such a combination might look like this: “537 farads + 1611 microfarads” or “62mm x 95cm x 77dm = ? cm^3”. The units of measurement combined in this way must naturally correspond to each other and make sense in a given combination.

If you check the box next to the "Numbers in scientific notation" option, the answer will be represented as an exponential function. For example, 4.339 881 565 445 3× 1031. In this form, the representation of a number is divided into an exponent, here 31, and an actual number, here 4.339 881 565 445 3. Devices that have limited number display capabilities (such as pocket calculators) also use a way of writing numbers 4.339 881 565 445 3E+ 31. In particular, it makes it easier to see very large and very small numbers. If this cell is unchecked, the result is displayed using the normal way of writing numbers. In the example above, it would look like this: 43,398,815,654,453,000,000,000,000,000,000 Regardless of the presentation of the result, the maximum accuracy of this calculator is 14 decimal places. This accuracy should be sufficient for most purposes.