**An electric element** is a structurally completed product manufactured under industrial conditions that is able to perform its functions as part of electrical circuits .

## Content

- 1 Basic parameters of electrical elements
- 1.1 Ratings
- 1.2 Accuracy class
- 1.3 Electric strength
- 1.4 Power
- 1.5 loss
- 1.6 Stability
- 1.6.1 Temperature effects
- 1.6.2 Mechanical stress

- 1.7 Reliability

- 2 See also
- 3 References
- 4 Literature

## Basic parameters of electric

### Nominal Values

- Nominal resistance R
_{n}or R_{nom}. - Nominal capacity C
_{n}or C_{nom}. - Nominal inductance L
_{n}or L_{nom}.

### Accuracy Class

Tolerance (or accuracy class) characterizes the tolerance of the value from the nominal and is *not an indicator of the quality of the* electrical element. The series of permissible deviations are described in GOST 9664-61 : ± 5, ± 10 and ± 20 are the most frequently used.

The tolerance limits are indicated as a percentage of the nominal value.

### Dielectric Strength

The ability of an element to withstand electrical loads without loss of performance is characterized by the following parameters:

*The operating voltage U*is the maximum voltage at which, under normal conditions, the element can remain for a guaranteed service life._{slave}*Rated voltage U*_{n}- Breakdown
*voltage or breakdown voltage U*is the_{CR}*minimum*voltage at which an insulation breakdown occurs. *The test voltage U*shows the maximum voltage at which the cell can be for a few seconds to a minute. Used for overvoltage._{isp}

### Power

*The rated power P _{n}* is the maximum allowable power that the element can dissipate during the guaranteed service life under normal conditions . As a rule, this parameter is indicated for resistors , since they are specifically designed to absorb electrical energy.

### Losses

Losses exist in any electrical element:

- Losses
*on active resistance*. *Dielectric*polarization*loss*due to imperfection of the dielectric.- Loss of resistance worn by various
*screens*,*parts cores*, etc. - Losses caused by various
*loads*. - The skin effect (surface effect) occurs with alternating current in a rectilinear conductor . It reduces the effective conduction area of the conductor to the annular part of the cross section. It arises due to the divergence of the lines of the magnetic field .
*The proximity effect*manifests itself in nearby conductors . Due to the mutual electrical interaction between the charge carriers in the conductors (for example, the Coulomb repulsive force between electrons ), the effective cross-sectional area decreases, and the losses increase.

These losses depend on the frequency , the nature of the conductor and on the surface roughness (the path of the current lengthens and the resistance increases). Parameters characterizing the loss:

*The loss tangent is tan δ*, where δ is the dielectric loss angle. It is determined by the ratio of the active power P_{a}to the reactive P_{p}at a sinusoidal voltage of a certain frequency.*Q factor Q.*For the coil, it is the inverse of tan δ.

The terms of quality factor and loss tangent are used for capacitors , inductors and transformers .

### Stability

*Stability of parameters* - is the ability of an electric element to maintain its properties when exposed to external factors, such as temperature, mechanical stress ( vibration , shock ), non-standard climatic conditions (elevated temperature , humidity or ambient pressure), etc.

#### Temperature effects

Temperature effects are divided into reversible and irreversible. A direct change in the characteristics of an element is described by temperature coefficients: TLC shows a change in parameter X with an increase in temperature T by one degree.$\alpha}_{X}=\frac{dX}{XdT$ .

- Temperature coefficient of resistance or TCS

$\alpha}_{R}=\frac{dR}{RdT$

- Temperature coefficient of capacity or TKE

$\alpha}_{C}=\frac{dC}{CdT$

- Temperature coefficient of inductance or TCI

$\alpha}_{L}=\frac{dL}{LdT$ In addition, you can give an example of an irreversible change in a parameter. Such changes can occur for various reasons, such as aging or a violation of the operating conditions.

- TKNE - irreversible change in capacity$TKHE=\frac{dL}{L}$ ,

where dT is the temperature increment, R is the resistance , C is the capacitance , L is the inductance .

#### Mechanical Impacts

Mechanical effects on the electrical element lead to catastrophic failures or cause leakage . The ratio of the electric element to mechanical vibrations is characterized by the following properties:

*Vibration resistance*is the property of an electrical*element to*withstand the damaging effects of vibration and, after prolonged exposure, retain the ability to perform its functions.*Vibration resistance*- the ability of an electric*element*to perform its functions under vibration conditions. The most dangerous resonance .

### Reliability

*Reliability* is the property of an element to perform all the specified functions for the required time under certain operating conditions, and to save the main parameters within the specified tolerances . Reliability is characterized by:

- Warranty period .
*The failure rate λ (t)*, that is, the ratio of the number of elements*n*that failed during the time*Δt*, to the product of the number of elements*n*that are workable by the beginning of the interval, by the duration of this interval*Δt*.$\lambda (t)=\frac{\mathrm{\Delta}n}{{N}_{n-\mathrm{one}}\mathrm{\Delta}t}$ To reduce the failure rate, you can use the lightweight mode of operation of the elements.- The likelihood of uptime.

## See also

- Radio parts

## Links

## Literature

- GOST 9664-61. The series of permissible deviations of physical quantities.
- GOST 12.1.012-90. Vibration safety. General requirements.